comp wont power on -_-

[bocochoco]

I built this comp about a year ago maybe a bit longer than that and just last night the cpu fan stopped working and the comp powered off beeping to tell me that it was overheating. I let it sit for a few hours to cool off and I put a temporary fan on the heatsink until I could replace it. It wouldn't immediately power back on when I pressed the power button, I had to unplug and replug and flip the switch on the psu a few times and it finally powered back on after I tested the psu by shorting the green and a black wire with a paperclip. The psu powered on just fine. Today the new fan came in and I put it on the heatsink and I am having the same problem as before. The light on the motherboard to tell me that it is getting power is lit but when I press the power button nothing happens--no beep, no spinning fans, no hard drive activity, no led's light up, nothing. I tried shorting the wires on the psu again and it powers on just fine, but I cant get the computer to turn on... What is going wrong here?

Mobo: Asus A8N-SLI deluxe
CPU: Athlon 64 X2 939
2GB ram, 2x geforce 7600GT in SLI.

 

[alvine]

power supply

 

[bocochoco]

power supply turns on fine when i use a paperclip to short the green and black wires...

 

[bocochoco]

well im not sure how or why this worked... and i wouldnt recommend that anyone do this... but i flipped the switch on the power supply to off and used a paperclip to short out the "turn me the hell on" wire to a ground and turned the psu on.. comp works fine now. I can't explain why this works... but it did...