power supply problem

[morgster]

I woke up one day and my PC was off, So i tried everything then thought it was my power supply that failed. So i bought a new one. i installed it correctly and tried to turn it on..Nothing, Dead silence :S. My CPU fan Spins about 1/4 of the way around. So i was just trying things and ended up unplugging the 4 pin 12v. And it turns on, but my monitor does not come on.
but when i plug in the 12v it does not turn on at all, but used too.
Can anyone explain why this is happening?
my pc is a AMD athlon kn96gm
.
I do not understand this at all.
thank you

 

[Deviousmind]

The 4 pin plug is to power your cpu the 20/24 pin is to power the rest of the m/b, wots prob happened is the 12v 4 pin rail has overheated at some point on the motherboard and is now creating a short on the m/b,
when unplugged the short is disabled and the 20/24 pin will power everything else on the board but not your cpu so nothing comes up on the monitor