This post will talk about setting up PowerPivot for Excel on the Windows Vista Operating System.  Before I talk about setup itself I want to mention the prerequisites.  On the Windows Vista platform, these requirements are different than those of Excel 2010.  They are:

• 32-bit and 64-bit platforms are supported.
• SP 2 (or later) - This is different than Excel and the reason for requiring this SP level is because PowerPivot for Excel on the Vista operating system requires the Platform Update for Windows Vista (more on that later).
• .NET 3.5 SP1 - PowerPivot for Excel requires .NET 3.5 SP1.  Note also that it requires this even if you have .NET 4.0 installed - if you have only .NET 4.0 installed PowerPivot installation will fail unless you also install .NET 3.51.
• Excel 2010 - PowerPivot for Excel requires Excel 2010.  It will not load on earlier versions of Excel.  An additional requirement with respect to Office install is that, when installing Office, you must also pick the "Office Shared Features" item in Office setup and, under Excel, you must make sure to install the ".NET Programmability" item as well.  In addition, you must install the processor architecture version of PowerPivot that matches Excel.  For Vista, this means if you have 32-bit Excel installed you must install 32-bit PowerPivot for Excel and if you have 64-bit Excel installed you must install 64-bit PowerPivot for Excel.

 Here are the steps needed in order to install PowerPivot for Excel on the Windows Vista operating system:

1. Make sure your operating system has Windows Vista SP 2 installed
   Windows Vista SP2 technet page is here: http://technet.microsoft.com/en-us/windows/dd262148.aspx.  Note that the install packages for SP2 require that SP1 is already installed.
2. If you don't already have it installed, install .NET 3.5 SP1
   You can install this from http://www.microsoft.com/downloads/details.aspx?FamilyID=ab99342f-5d1a-413d-8319-81da479ab0d7&DisplayLang=en
3. Make sure that the Platform Update for Windows Vista is installed on the machine
   Information is here: http://support.microsoft.com/default.aspx/kb/971644?p=1.  The Platform Update for Windows Vista is available via Windows Update.
4. Install Excel 2010
   Be sure to include "Office Shared Features"
5. Install PowerPivot for Excel
   Currently, the pre-release version can be installed from http://www.powerpivot.com/download.aspx.

 After you complete these steps, start Excel 2010.  If everything went well, Excel will attempt to load the PowerPivot for Excel add-in.  When the dialog comes up asking whether to allow the add-in to be loaded, click on the button allowing it.  Once the add-in is loaded you should see a new tab in the Excel ribbon labeled "PowerPivot."  If that tab appears, setup succeeded.

FAQ (feel free to add questions in the comments to this post and I will update with answers):

Q: