Try to manually startingstart the SharePoint 2010 Timer service.
For some reason after upgrading from WSS 3.0 SP2 > WSS 3.0 SP3 > SPF 2010 > SPF 2010 SP1, when I tried to manually start this service I received login failed error.
If you do receive the login failed error, like i did, then reset the login account's password in the computer management.
Again, manually start the service.
If the timer service starts, then run the SP Configuration Wizard (run as administrator)