Buddies computer wont turn on

[naldo]

A guy in my dorm asked me to look at his computer to see if I can fix it and I am stumped. When you press the power button the fans spin up for a second but then the machine cuts right off. So I figure it must be the Powersupply, the psu he has in there is 350W, but has crappy ratings on the rails. So I go and get a spare PSU I had on hand to go test (this PSU has less watts but more amps on the rails), the machine still doesnt power up. I disconnect power to everything but his motherboard (ATX connector and 12V 4-pin square thing), machine still does the same thing. So it must not be a Power Issue.

Can anyone think of what might be wrong?

 

[neovan]

Fried mobo?

 

[PCHPlayer]

MB shorting out on the case? Try running with the MB outside the case.

 

[jackschmittusa]

Either a short as PCHPlayer suggested (though they normally only appear on assembly, not later after normally functioning), or the mb is not receiving the speed signal from the cpu fan, which I think more likely.

 

[mechBgon]

What brand and model of motherboard is it?

 

[airfoil]

Check to see if the CPU fan is spinning up to full speed - could be an issue with the CPU overheating.