How can I tell what's wrong with this busted G4 I just bought? I assume it could be the easy to replace PSU, but I fear it could be the dreadful *gulp* FATHERBOARD!!! When I press the power button, I get NOTHING! No beeps, no whirs, I don't see a fan stutter and the LED doesn't do a thing. Also, how can I tell if it's dual or single CPU? It just says "1.25ghz" on the back label.