VISTA can't shutdown my computer UNLESS it hibernates first!

[Gravel]

Thankfully this is my secondary computer i speak of and not my gaming rig. For some reason, my secondary computer is only able to shutdown properly if I put it to sleep/hibernate first AND THEN click Shutdown. If I don't do this, VISTA shuts down, the screen loses signal, but the computer STAYS ON. I can only truely shut it down if I hold down the switch for a few seconds. The exact same thing happens when I tell it to restart! The computer just hangs there doing nothing.

For some reason, vista is able to restart proplerly whenever updates and drivers require the computer to restart. But clicking RESTART myself causes the computer to just hang.