I woke up dismorning and my computer was turned off, I left it on the night before though. I tried to turn it on, and alas, all it did was flicker the lights for One Second really and turned itself back off. After tinkering with the cables and what not and resetting the motherboard, I got the computer to turn on, but not boot up. Then after some more tinkering,I got the computer to boot up successfully and run as it normally did. After using it for 20 minutes however, the computer shut its self back off again, and now Im back in the same boat, except I can't get it to work again. Ideas?

What do you mean by "resetting the motherboard," Your symptoms could relate to a powersupply failure or it could be just the heatsink fan on the CPU. It may also be any of several other things When seeking help on a technical forum terms such as "a bit of tinkering" are not helpful in describing exactly what you have done. First question. Is this a laptop or desktop system? Second question. Is it a brandname or custombuilt? If it is a desktop open the case. When you try to boot do any fans spin? Is the heatsink fan gummed up with dust buildup? Do you get any POST beeps? Goin' Fishin' (Some day)

Resetting the motherboard as in moving that small orange chip thing over to the reset position then moving it back after the few seconds is what I meant. My apologies, by tinkering I meant, shifting connections around to other available plugs such as the periphial connections, remounted my Processor, changed out some cables that connected the dvd, sata hd, and the extra fans with new ones. Its a desktop computer, I built it myself, 2 or 2.5 gigs of ram, maybe 3 don't quite remember, 2.4ghx intel celeron dual core processor, and the mother board... really dont remember. xD After opening the case up, there was dust build up, i've done cleaned the hell out of it, not a spec of dust left in that thing. When attempting to turn it on the fans do indeed spin, but like I said before, the power to them shuts off before I even remove my finger from the button. No POST beeps.

ok Strip it down to barebones. ie disconnect all drives, take out all but 1 stick of RAM, Leave only Motherboard, Powersupply, CPU with heatsink/fan, Graphics card and keyboard. Diagnosing the problem from here is a matter of testing with known good components. Goin' Fishin' (Some day)