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 ” .
1, Open Regedit
2, Navigate to HKLMSYSTEMCurrentControlSetControlSession 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
HKLMSYSTEMCurrentControlSet001ControlSessionManager HKLMSYSTEMCurrentControlSet002ControlSession Manager
6, Attempt to rerun the checks and all should be ok 🙂