If you happen to get the "Restart Computer" rule Failed while trying to install Microsoft SQL Server 2008 R2, the only thing you need to do is Clear the PendingFileRenameOperations key in your registry. You can find the key in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager. You can start the Registry Editor running the Regedit.exe
Afterwards, just rerun the test, and voila, it will pass.
Hope i saved you some time!