Today I will be talking about one of the features included in the new IIS Admin Pack called Configuration Editor.

Configuration Editor is an IIS Manager feature that will let you managed any configuration section available in your configuration system. Configuration Editor exposes several features from configuration that are not exposed anywhere else in IIS Manager, including:

1. Schema Driven - Config Editor is entirely driven by the configuration schema (found in \windows\system32\inetsrv\config\schema\), this means that if you extend the configuration system creating your sections, they will be available for managing inside config editor, no need to build additional UI for them.
2. Additional Information - Config Editor exposes more information such as the deepest place where the section is being used, or where a particular element in a collection is coming from (where is it inherited from?), etc.
3. Script Generation - Allows you to make changes and it generates the code to automate those tasks, generating Managed Code (using Microsoft.Web.Administration), JavaScript (using AHADMIN) or Command Line (using AppCmd).
4. Searching - Allows you to quickly perform scoped searches of the configuration system for all the sections and where they are being used, becoming a great way to get a bigger picture of the server as well as to prevent configuration locking violations and many other uses.
5. Locking - Allows you to do advanced locking such as locking specific attributes so that they cannot be used in deeper locations, lock individual items in a collection or lock the entire section, etc.

Please give us feedback on things you would like to see or change at the IIS Forums: http://forums.iis.net/1149.aspx

OK, but rather than keep with more and more text, I will just show you a video on how it looks and all its features (for those of you who like text, there is a transcript below).

Transcript:

So I have here Windows Vista SP 1 with the IIS Admin Pack installed, in my machine I have very few applications installed but should be good to show some of the features on config editor. When entering Config Editor, first thing you will notice is that at the top you have a drop-down list that shows all the sections currently schematized and ready to be used in your system.

Since this is sorted alphabetically, the first section that gets selected is AppSettings, for I can very easily switch between ASP.NET configuration sections, such as system.web/authentication, or the IIS configuration sections such as system.webServer/defaultDocument or the system.applicationHost/sites that contains all the sites configuration for IIS.

As you can see the user interface displays the configuration elements and properties of the section that is selected, providing you an easy way to see every single configuration property available in the system.

At the top you'll get a label specifying the deepest path where this section is being used relevant to your scope, so in this case its telling us that its been set in ApplicationHost.config. After that, all the elements and properties are shown in a Property Grid, that displaye elements as a collapsible set of properties. One of the interesting things is that we provide validation for the properties for example, when entering string characters in a numeric property type an error message will be displayed giving you the details of the expected types. Additionaly other benefits such as type editors, so that when editing a property of type boolean, you get the True/False drop-down, or when a property that is of type enumeration such as the LogFormat inside the SiteDefaults, you will get a drop-down list with only the list of options that are allowed for that enumeration. Same way, when editing a property of type flags such as the logExtFileFlags that contains the fields to include in the log file, you will get a multi-select drop-down list where you can select and de-select the different options. Also, you will notice that additional information is displayed as you select the different properties, giving you details of their data type as well as additional validations for those that have some, for example, the truncateSize property has specified that only a certain range is considered valid, if I type a value that is not within that range it will show this message giving me details of the problem.

Making Changes

Now, lets move to a simpler section so that we can show other features of the Configuration Editor. For example here in default documents, if I want to disable it I just change it to False and click Apply. As you would expect all the changes are applied and to see what changes this actually made in my system I'm going to show a Diff of the configuration that I have backed up and indeed the only change that happened in my configuration system is that it changed from true to false.

Collection Editor

As you will notice there is a collection in this section, all the collections are shown in an advanced collection editor that will let you see all the information of the items on it, including the ability to add, remove and clear the collection, as well as lock individual items on it. It additionally shows where each of the individual items is coming from making it easier to understand the distributed configuration.

Another thing you will notice is that this collection editor shows some visual cues to help you deal with data, for example this little key here tells you that this property is the unique key of the collection item.

So lets actually add a new one, for that I just need to click Add and fill the values, in this case, lets add Home.aspx as a new default document. After doing that, I can close dialog and click Apply. And lets take a look at what happened to my configuration. As you can see the new item was added. So as you can see its really easy to see and change configuration in collections.

Script Generation

Now, one of the interesting things that it also has is those changes that I just did, its great but sometimes I don’t want to apply them immediately but instead automate them so that I can apply them at a later time. For example, lets just change the attribute Enabled back to true, and rather than just applying the change as we did before, I want to generate the script cause probably I'm creating a provisioning script for my site and I want to include this as part of it, so just by clicking Generate Script I get this dialog that gives you the code for Managed Code using Microsoft.Web.Administration in C#, and as you can see its quite easy to read. It also gives you JavaScript code that uses a COM library that our configuration system ships called Microsoft.ApplicationHost, and just as the managed code version it just sets the value. It also gives you command line for it, so you don’t need to build code or scripts, you can just run the command line and to prove that, lets actually just run this command line. First lets show the diff again so that we see that its set to false. Now lets run the command line AppCmd which lives in Inetsrv directory. Now lets show the difference again, and as you can see it actually sets the value as expected. As you can see this will help you write scripts or code to manipulate IIS and ASP.NET settings without requiring additional knowledge.

Locking

Another interesting feature is locking, for example if I want to make sure that my default documents are always enabled and no one else can override them, I can go here and select the enabled attribute and click lock attribute which will prevent it from being changed in any other web.config file.

Search Configuration

Now, another interesting feature which is probably one of the most powerful features is the ability to search configuration so that you can see a high-level overview of the configuration system and all the web.config files on it. Just click Search Configuration. This shows me this dialog that shows me the root web.config that includes all the section that are being set on it, it also shows me applicationHost.config that includes again all the sections being used on it, as well as a location tag for a particular application that includes also some sections for it. you will notice that I also have a couple of applications that include web.config's in their folders, and sub-folders. where we can see how for example in this web.config it includes some

one of the neat features is that you can actually click any of this nodes and it will immediately display the content of the section as well as where its coming from. For example if I click the web.config my entire web.config is displayed, if I click a specific section it only displays the content of the section. I can even click the locationPath that I'm interested and only get that particular one.

Additionally you can easily search who is changing the authorization settings from asp.net and as easy as that you can see all the places in your server where the authorization settings are being set and quickly identify all the settings that are being used in your server. This feature is extremely useful because now, you can easily search for example default Document and make sure nobody is changing it and make sure no one else is violating the locking we just did.

It also allows you to see the files in a flat view where it gives you all the different paths and files where each of them is coming from. You get the exact functionality, its just a different visual representation of the config.

Schema-Driven

Another interesting thing is that if you want to build your own sections and extend our configuration system, you can go to the schema folder and write your own configuration section, declare it using our schema notation, here I'm just defining a section named mySection, that includes an attribute called enabled of type bool and an attribute called message of type string and an attribute password of type string that should be encrypted.. Now, I just need to edit applicationHost.config to define the section so that config system knows we are going to consume it . Just by doing that, now I can go back to config editor and refresh the window, and my section is now available in the drop down, and as you would expect it displays all of the properties I defined, and I can just go ahead and set them, and I get all the locking functionality, I get all the script generation, I get all the UI validation.

And if I apply, you will see that as expected the changes are done, the password attribute is encrypted, etc.

So as you can see configuration editor is an extremely powerful feature that will be really useful for successfully managing the web.config's in your system.

Extending the Hierarchy Tree View in InetMgr

InetMgr exposes several extensibility points that developers can use to plug-in their own features and make them look and feel just as the built-in functionality. One of those extensibility features is the hierarchy tree view and is exposed mainly through three classes:

1. HierarchyService. This class is the class that handles the entire hierarchy and an instance is provided by the UI and you can get a reference to it through a ServiceProvider. It is used to manipulate the tree view programmatically, exposing methods to perform actions such as Select, Delete, Refresh, etc.
2. HierarchyInfo. This abstract class represents a node in the tree view, for example the Web Sites node, the Default Web Site's node, the connections node are examples of instances of HierarchyInfo’s. This class has properties like Text, Image and allows you to react to actions such as selection, deletion, etc. Developers extending the tree view will need to create their own derived classes to implement the behavior as explained below.
3. c) HierarchyProvider. This abstract class is the base class for all the features that want to extend the tree view. HierarchyService will query each of the registered providers to create the treeview. Developers that wish to add their own nodes should register a HierarchyProvider through the IExtensibilityManager interface.

To extend the Tree view to add your own set of nodes or context menu tasks, developers need to perform the following actions:

1. Create a class that derives from HierarchyProvider and handles the GetChildren and/or GetTaskItems to provide any nodes or tasks as needed.
2. Register the HierarchyProvider using the IExtensibilityManager, this is typically done during the Module initialization phase.
3. 3) Handle navigation and syncronization as needed.

 

Tasks illustrated in this walkthrough include:

• Creating a HierarchyProvider and creating HierarchyInfo classes
• Registering a HierarchyProvider
• Testing the new feature

Note:
This walkthrough is a continuation from the previous three walkthroughs you can find on how to extend InetMgr.
You can find the first three at:

• Creating a Simple UI Module
• Creating a Module Page for IIS7 Administration Tool
• Adding Configuration Functionality to IIS7 Admin Tool Extensions

Task 1: Creating a HierarchyProvider

HierarchyProvider is the base class that developers need to inherit from in order to get calls from the UI whenever a node needs to be loaded. This way they can choose to add nodes or tasks to the HierarchyInfo node that is passed as an argument.

 

To create a HierarchyProvider

Back in Microsoft Visual Studio 2005 in the ExtensibilityDemo solution, select the option Add New Item from the Project Menu. In the Add New Item dialog select the Class template and type DemoHierarchyProvider.cs as the name for the file. Change the code so that it looks as follows: using System; using Microsoft.Web.Management.Client; namespace ExtensibilityDemo {     internal class DemoHierarchyProvider : HierarchyProvider {         public DemoHierarchyProvider(IServiceProvider serviceProvider)             : base(serviceProvider) {         }         public override HierarchyInfo[] GetChildren(HierarchyInfo item) {             if (item.NodeType == HierarchyInfo.ServerConnection) {                 return new HierarchyInfo[] { new DemoHierarchyInfo(this) };             }             return null;         }         internal class DemoHierarchyInfo : HierarchyInfo {             public DemoHierarchyInfo(IServiceProvider serviceProvider)                 : base(serviceProvider) {             }             public override string NodeType {                 get {                     return "DemoHierarchyInfo";                 }             }             public override bool SupportsChildren {                 get {                     return false;                 }             }             public override string Text {                 get {                     return "Demo Page";                 }             }             protected override bool OnSelected() {                 return Navigate(typeof(DemoPage));             }         }     } }

The code above creates a class derived from HierarchyProvider that implements the base GetChildren method verifying that the node that is being expanded is a ServerConnection; if that is the case it returns an instance of a DemoHierarchyInfo node that will be added to that connection. The class DemoHierarchyInfo simply specifies its NodeType (a non-localized string that identifies the type of this node), SupportsChildren (false so that the + sign is not offered in tree view) and Text (the localized text that will be displayed in the tree view). Finally it overrides the OnSelected method and performs navigation to the DemoPage as needed.

Task 2: Registering the HierarchyProvider

In this task we will register the hierarchy provider created in the previous task so that the HierarchyService starts calling this type to extend the tree view.

To register the provider

Back in Microsoft Visual Studio 2005, open the file DemoModule.cs, and add the following code at the end of the method to register the provider: IExtensibilityManager extensibilityManager =     (IExtensibilityManager)GetService(typeof(IExtensibilityManager)); extensibilityManager.RegisterExtension(     typeof(HierarchyProvider),     new DemoHierarchyProvider(serviceProvider)); The entire code should look as follows: protected override void Initialize(IServiceProvider serviceProvider,                                    ModuleInfo moduleInfo) {     base.Initialize(serviceProvider, moduleInfo);     IControlPanel controlPanel =         (IControlPanel)GetService(typeof(IControlPanel));     ModulePageInfo modulePageInfo =      new ModulePageInfo(this, typeof(DemoPage), "Demo", "Demo Page");     controlPanel.RegisterPage(modulePageInfo);     IExtensibilityManager extensibilityManager =         (IExtensibilityManager)GetService(typeof(IExtensibilityManager));     extensibilityManager.RegisterExtension(         typeof(HierarchyProvider),         new DemoHierarchyProvider(serviceProvider)); }

Task 3: Testing the new feature

To test the feature

Compile everything using Build Solution from the Build Menu and run InetMgr.exe from the <Windows>\System32\InetSrv directory. Connect to localhost using the TreeView and expand the server connection node. This will show the new node underneath the connection. When you click on it, it will navigate to the demo page just as expected:   Furthermore, the breadcrumb at the top of the UI will automatically discover it and you will be able to navigate to the page by clicking on it, as well as using the text editing and intellisense feature it provides.

 

Next Steps

In this lab, you learned how to extend the tree view to customize any node on it and add your own nodes to it. You can also override the GetTasks method to provide context menu tasks for existing nodes, and you can also override the SyncSelection method to customize the way synchronization of navigation works.

Today somebody asked a question about how to manage some ASP.NET configuration settings such as changing the trust level of the application and adding a few application settings and changing compilation settings to debug. I thought it would be trivial to search the web for an article or something that would show the features we added in IIS 7.0 to manage those, but to my surprise I was not able to find anything that would clearly show it, so I decided to write this pretty quickly for anyone that is not aware.

With the release of IIS 7.0 (included in Windows Vista and Windows Server 2008), and of course included in IIS 7.5 (Windows 7 and Windows Server 2008 R2) we added a set of features for managing some of the configuration of common ASP.NET features inside the same IIS Manager. Those features include:

1. .NET Authorization Rules ¹ – To manage the authorization rules for ASP.NET, this is particularly useful when using Classic Mode. This UI basically is to manage the system.web/authorization section in a graphical way.
2. .NET Compilation – This exposes the settings used by the ASP.NET compilation engine, such as list of assemblies, Debug settings, VB settings (Option Strict, Option Explicit), Temp directory, etc. This UI saves all the settings in the system.web/compilation section.
3. .NET Error Pages ¹ – Allows you to manage the ASP.NET custom errors, exposing the system.web/customErrors.
4. .NET Globalization – Allows you to manage the globalization settings such as file encoding, ui culture, etc. This modifies the section system.web/globalization
5. .NET Providers ² – Allows you to manage the different provider configuration for the ASP.NET providers, such as Roles, Membership and Profile. (system.web/membership, system.web/profile, system.web/roleManager, etc).
6. .NET Users, .NET Roles and .NET Profile ² – Configure options that track settings for ASP.NET applications. All these features uses the ASP.NET runtime configuration to allow you to manage their settings, such as adding users, roles and profile settings. (What this post is about). These does not modify configuration but instead they use the Provider configured (such as SqlMembershipProvider, SqlRoleProvider, WindowsTokenRoleProvider, etc)
7. .NET Trust Levels, allows you to configure the security trust level policy for the application. Modifies system.web/trust section.
8. Application Settings – Allows you to manage the name/value pair stored in the .NET appSettings section.
9. Connection Strings – Configures the database connection strings that can be used by ASP.NET applications. Manages the connectionStrings section.
10. Machine Key – Allows you to modify the machine key and other related settings stored in system.web/machineKey section.
11. Pages and Controls – Allows you to modify settings from the system.web/pages section, such as Base class, Namespaces, and Controls registered.
12. Session State – Allows you to configure the session state settings such as connection string, cookie configuration and other configuration included in system.web/sessionState.
13. SMTP E-mail – Configure the SMTP settings such as Server, Delivery mode, or Pickup directory, included in system.net/mailSettings/smtp section.

¹ – These features are included in Windows 7 and Windows Server 2008 R2, but can be installed for Windows Vista and Windows Server 2008 when downloading the Administration Pack for IIS7.

² – Note, these features require hosting the ASP.NET runtime and due to technical limitations only application pools configure to run using .NET Version 2.0 will show these features. This means that if you configure your application pool to run .NET 4.0 (in IIS 7.0 and IIS 7.5) you will not see those features. As a workaround you could temporarily change the application pool to run in 2.0, make your changes and switch it back to 4.0 (of course, not recommended for production environments).

These features are not meant to expose all the settings included in ASP.NET, and they only include configuration settings up to .NET 2.0. I should also add that IIS includes a generic configuration editor that allows you to manage a lot more configuration settings from ASP.NET, IIS, and more, in the image below you can see a lot more sections like webParts, trace, siteMap, and others:

The best thing is that you can apply the changes immediately or you can also make changes and just generate the code to automate them later using code, command line or scripts them using Javascript, Managed code, or AppCmd.exe.

NOTE: RTM has been released see the following blog: http://blogs.msdn.com/carlosag/archive/2008/03/04/IISManagerForWindowsXPand2003andVista.aspx 

With the release of Windows Server 2008 RC0, in IIS we are also releasing the ability to manage the Web Server, the new FTP Server and the new modules remotely using IIS Manager 7.0.

In the past with previous Beta we shipped similar functionality under a different name, however for the first time this is the real way we will be supporting this remote administration from different Windows versions when Windows Server 2008 final version comes along.

The reason this release in particular is exiting is because for the first time all the UI extensibility is enabled for these platforms making it possible to build your own UI modules, install them in the server and have the clients that connect to your server automatically download the new functionality and use it as it was part of the IIS Manager release.

Another reason this is important for us is because this is the first time we are releasing support for x64 which is something required for customers using Windows Vista 64 bit edition or any other 64 bit version of Windows.

You can download and install them from:

x86

http://www.iis.net/downloads/default.aspx?tabid=34&g=6&i=1524

x64

http://www.iis.net/downloads/default.aspx?tabid=34&i=1525&g=6

Note: This RC0 version will not be able to connect to any other older build of Windows 2008 Server including Beta 3, so if you need to still manage Beta 3 version you will need to install the Beta 3 build of the tool which can safely live side-by-side with the RC0 build.

My last post talked about the Technical Preview release of the IIS 7.0 Admin Pack, and how it includes 7 new features that will help you manage your IIS 7.0.

Today I was going to start writing about more details about each feature and Bill Staples just posted something (How to (un)block directories with IIS7 web.config) that almost seems that it was planned for me to introduce one of the features in the Admin Pack, namely Request Filtering UI.

IIS 7.0 includes a feature called Request Filtering that provides additional capabilities to secure your web server, for example it will let you filter requests that are double escaped, or filter requests that are using certain HTTP Verbs, or even block requests to specific "folders", etc. I will not go into the details on this functionality, if you want to learn more about it you can see the Request Filtering articles over http://learn.iis.net

In his blog Bill mentions how you can easily configure Request Filtering using any text editor, such as notepad, and edit the web.config manually. That was required since we did not ship UI within IIS Manager for it due to time constraints and other things. But now as part of the Admin Pack we are releasing UI for managing the Request Filtering settings.

Following what Bill just showed in his blog, this is the way you would do it using the new UI instead.

1) Install IIS Admin Pack (Technical Preview)

2) Launch IIS Manager

3) Drill down using the Tree View to the site or application you want to change the settings for.

4)  Enter into the new feature called Request Filtering inside the IIS category

5) Select the Hidden Segments and choose "Add Hidden Segment" from the Task List on the right

6) Add the item

As you would expect the outcome is exactly as Bill explained in his blog, just an entry within you web.config, something like:

So as you can see the Request Filtering UI will help you discover some of the nice security settings that IIS 7.0 has. The following images show some of the additional settings you can configure, such as Verbs, Headers, URL Sequences, URL Length, Quey String size, etc.

I have just uploaded a new application that extends IIS Manager 7 for Windows Vista and Windows Longhorn Server that adds a new Reports option that gives you a few reports of the server and site activity. Its features include:

• Reports are scoped on the object selected in IIS Manager, so if server is selected you get a server report including all Sites information, if a site is selected you only get information related to that specific site
• Export to HTML
• Printing support
• Different chart options: Pie, Columns and Lines
• Built-in Reports:
• Status Code, Hits Per Url, Hits by Hour, User Agent, File Extensions
• Users, Time Taken, Win32 Errors, Client Machine, Http Method

Click Here to go to the Download Page

I'm working on a second version that will allow you to create your own queries and configure more options like Chart settings, and ore.

If you have any suggestions on reports that would be useful feel free to add them as comment to the post.

During my last two business trips (to Barcelona for TechEd and Mexico for ReMix) I was way too bored on the plane and since I recently got my Motorola Q9 (which is a sweet Windows Mobile Phone) decided to write myself a Tetris game and to port my Sudoku game to Windows Mobile as a way to do my "first steps" in the .NET Compact Framework.

To my surprise it was really easy to write them and even more to port the desktop version of Sudoku to run in all the .NET Compact Framework platforms.

Since holidays are coming I thought of share them as a gift for this holiday's season.

Bottom line (with the risk of sounding like a marketing dude, which I'm not) .NET is a cool technology that makes it really easy to code for many devices, from high-end servers to hand held devices to mobile phones. In this case, I have tested these applications with a Pocket PC, Smartphone 2003, Windows Mobile 5 and Windows Mobile 6. And best of all, the code base is pretty much the same as the Desktop version.

You can install both games by browsing from your mobile device to http://www.carlosag.net/mobile/ where you will find instructions on how to install the .cab files, or just click the images below to go to the download page for each game.

           

 Happy holidays!

 

 

With the upcoming release of .NET 3.5 and LINQ I thought it would be interesting to show some of the cool things you can do with IIS 7 and LINQ. Everything that I will do can be done with C# 2.0 code but it would take me several lines of code to write them but thanks to LINQ you can do them in about a line or two.

Let's start with a very basic example that does not use LINQ but just M.W.A (Microsoft.Web.Administration) and then start adding interesting things to it.

The following code just iterates the sites in IIS and displays their name.

Now, let's say I wanted to have them sorted by their name. This is where LINQ starts being useful
Say you want to start all the sites that are stopped:
OK, now let's imagine I want to find all the applications that are configured to run in the Default ApplicationPool and move them to run in my NewAppPool. This would take me a lot more lines of code but now I can just do:
Now let's say I want to find the top 20 distinct URL's of all the requests running in all my worker processes that has taken more than 1 second.
OK, finally let's say I want to display a table of all the applications running under DefaultAppPool and display if Anonymous authentication is enabled or not. (Now this one is almost on the edge of "you should do it differently, but it is Ok if you are only reading a single value from the section):
As you can see LINQ is an incredibly useful feature in C# 3.0 and in conjunction with Microsoft.Web.Administration allows you to do incredibly complex operations in IIS with just few lines of code.

Today we are releasing the IIS Search Engine Optimization Toolkit. The IIS SEO Toolkit is a set of features that aim to help you keep your Web site and its content in good shape for both Users and Search Engines.

The features that are included in this Beta release include:

• Site Analysis. This feature includes a crawler that starts looking at your Web site contents, discovering links, downloading the contents and applying a set of validation rules aimed to help you easily troubleshoot common problems such as broken links, duplicate content, keyword analysis, route analysis and many more features that will help you improve the overall quality of your Web site.
• Robots Exclusion Editor. This includes a powerful editor to author Robots Exclusion files. It can leverage the output of a Site Analysis crawl report and allow you to easily add the Allow and Disallow entries without having to edit a plain text file, making it less error prone and more reliable. Furthermore, you can run the Site Analysis feature again and see immediately the results of applying your robots files.
• Sitemap and Sitemap Index Editor. Similar to the Robots editor, this allows you to author Sitemap and Sitemap Index files with the ability to discover both physical and logical (Site Analysis crawler report) view of your Site.

Checkout the great blog about IIS SEO Toolkit by ScottGu, or this IIS SEO simple video of some of its capabilities.

Run it in your Development, Staging, or Production Environments

One of the problems with many similar tools out there is that they require you to publish the updates to your production sites before you can even use the tools, and of course would never be usable for Intranet or internal applications that are not exposed to the Web. The IIS Search Engine Optimization Toolkit can be used internally in your own development or staging environments giving you the ability to clean up the content before publishing to the Web. This way your users do not need to pay the price of broken links once you publish to the Web and you will not need to wait for those tools or Search Engines to crawl your site to finally discover you broke things.

For developers this means that they can now easily look at the potential impact of removing or renaming a file, easily check which files are referring to this page and which files he can remove because of only being referenced by this page.

Run it against any Web application built on any framework running in any server

One thing that is important to clarify is that you can target and analyze your production sites if you want to, and you can target Web applications running in any platform, whether its ASP.NET, PHP, or plain HTML text files running in your local IIS or on any other remote server.

Bottom line, try it against your Web site, look at the different features and give us feedback for additional reports, options, violations, content to parse, etc, post any comments or questions at the IIS Search Engine Optimization Forum.

The IIS SEO Toolkit documentation can be found at http://learn.iis.net/page.aspx/639/using-iis-search-engine-optimization-toolkit/, but remember this is only Beta 1 so we will be adding more features and content.

Every now and then after leaving my computer running for several weeks I would get a weird error message when trying to launch Excel saying something like:

C:\PROGRA~1\MICROS~1\Office12\EXCEL.EXE is not a valid Win32 application.

or

This file does not have a program associated with it for performing this action. Create an association in the Set Associations control panel.

I tried several things to make it run again, but only a restarting would solve the problem. Finally, I decided to investigate a bit more and turns out there is a fix that solves the problem that you can download from Microsoft support:

http://support.microsoft.com/kb/952709

This update improves the reliability of Windows Vista SP1-based computers that experience issues in which large applications cannot run after the computer is turned on for extended periods of time. For example, when you try to start Excel 2007 after the computer is turned on for extended periods of time, a user may receive an error message that resembles the following:

EXCEL.EXE is not a valid Win32 application

I just installed it and so far so good, no more weird errors but I guess I need to wait a few weeks before I can testify it works. Either way I though this could be helpful for others.

Direct links for the fix download are:

Windows Vista, 32-bit versions
Download the Update for Windows Vista (KB952709) package now. (http://www.microsoft.com/downloads/details.aspx?FamilyId=DF72A9B0-564E-4326-894E-05CBA709CB39)
Windows Vista, 64-bit versions
Download the Update for Windows Vista for x64-based Systems (KB952709) package now. (http://www.microsoft.com/downloads/details.aspx?FamilyId=C3536CAA-7B71-4525-9D23-21A5B3D4507F)