PC Won't Do Anything Unless the CPU Power Is Disconnected

[Pandamobile]

My friend's PSU died the other day, so I'm trying to hook him up with one of my spare 750W's. Problem is, the PC only does a short burst of fan spins when it starts up. Push the power button, fans rev, then they go off, and nothing.

I started disconnecting things one by one, til I was left with just the CPU on the motherboard. That still didn't do anything, so I unplugged the 4 pin CPU power connector and the pressed the power button and everything kicked in. The harddrives revved up, the fans stayed on, etc.

So I'm wondering, doe sthis mean a dead CPU? It's an Athlon X2 6400 on a Gigabyte GA-M55-SLI AM2 motherboard.

[[EG] Pepper]

nah, just a dead fan that is all

a new socket AM2 cooler is all you need

[editline]01:53AM[/editline]

thought you meant the 4 pin fan plug

i think it is the motherboard that has died.