[Wrathcaster]

So last night I'm late up working on some school shit before i hit the sack, and for no apparent reason at all, the bastard computer just turns off on me. The monitor had power the whole time but just went black as the tower simply died. The power button doesn't do shit, and I've tried rearranging the plug ins and changing sockets but nothing's working. Been waiting for my PC's manufacturer (ibuypower.com) to get back with me for some tech support, but I have a feeling I might have to fix this one myself.

The computer itself is an Athlon XP 3000+ on a A7n8X mobo, with 1024 mb DDR RAM, a Geforce 5600 FX 256 mb, Soundblaster Audigy 2, Western Digital 160 gb 7200 RPM hard drive, Lite-On 52x24x52 CDRW, and a 16x DVD drive. It's all powered by the 420 watt power supply that came with my Raidmax Scorpio 668 case.

The computer has never run too hot, the interior case temps always staying between 26-29 celcius, depending on whether it's idle or not. Up until now the rig's been super cool, never had any problems, and the inside of the case doesn't appear to have any obviously damaged components ie: burn marks, melting, etc... It looks fine to me, but for some reason it won't power up. Of course, I'm suspecting the power supply, but have no way of testing out my theory that it may be burned out. Any suggestions on the best way to troubleshoot/fix this myself?