When installing SQL Server 2005 RTM/SP1/SP2 and SQL Server 2008 RTM on Windows 7 RC it presents you with a warning message. The message says that this SQL Server version has a known compatibility issues with Windows 7 RC. This warning is genuine and applies to all SQL Server editions, including all Express editions. The incompatibility was fixed in SQL Server 2008 Service Pack1 and SQL Server 2005 Service Pack 3.

You can safely continue the installation by clicking "Run program" button and apply the latest service pack afterwards. In some cases you may be presented with this warning message multiple times during the installation process.

Once the installation is complete please apply the latest SQL Server service pack. You can use Windows Update to do so. Just be sure to click "Get updates for more Microsoft products" to start obtaining updates for SQL Server. SQL Server service packs should show up on the list of optional updates. You may need to kick-off the scan for updates manually if not - you can do it by clicking "Check for updates" link on the left pane of main Windows Update window.

If for some reason Windows Update doesn't work for you, please download and install latest service pack manually.

Download SQL Server 2005 Service Pack 3

Download SQL Server 2008 Service Pack 1

If you're installing SQL Server 2005 Express (any Express edition) or SQL Server 2008 Express (Runtime Only) you can just download the SQL Server Express package containing the latest service pack. This may seem counter-intuitive if you already have some Express package, but installing it and then downloading and applying service pack is going to take longer than downloading a package already containing the latest service pack and installing it. Plus, in case of SQL Server 2008 Express the service pack package is actually bigger than the SQL Server Express package, since the service pack is shared with all SQL Server 2008 editions.

Download SQL Server 2005 Express Edition SP3

Download SQL Server 2005 Express Advanced Edition SP3

Download SQL Server 2005 Express Toolkit Edition SP3

Download SQL Server 2008 Express SP1

If you need to install SQL Server 2008 Express edition other than Runtime Only on Windows 7 RC and need to avoid the warning dialogs, you can create SQL Server 2008 with Service Pack 1 package yourself. Please follow steps described by Peter Saddow here.

Creating a merged (slipstreamed) drop containing SQL Server 2008 RTM + Service Pack 1

-  Krzysztof Kozielczyk