I came across this issue when trying to upgrade to SQL 2008 sp1, where one of the checks failed and would not allow me to update. The check was  “‘Reboot required ” .

Solution

1, Open Regedit

2, Navigate to HKLM\SYSTEM\CurrentControlSet\Control\Session Manager

3, Go to the properties of the following DWORD Value “PendingFileRenameOperations”

4, Remove any data in this value (so this is blank)

5, Do the same again for the following keys

HKLM\SYSTEM\CurrentControlSet001\Control\SessionManager                                                     HKLM\SYSTEM\CurrentControlSet002\Control\Session Manager

6, Attempt to rerun the checks and all should be ok