My computer went boom.

[Eaglestrike]

So I was playing a game and of course during a critical part of it my computer just turned off. It was like the power went out, except my lamp didn't blink and...my computer won't turn on. I have been a bad owner and haven't gotten any compressed air to clean out all the dust in the thing for a long time, I'm going to guess that was the cause of it. But my computer went boom and isn't turning back on.

What I'd like to know is:
1) Would the most likely part be the motherboard? Or is the processor also likely to be dead?
2) How sure could someone be that it's only one of the two above, and not something else entirely/both/all of the above?

Basically could I get a cheap part to be able to play until I can get a whole new computer? I'm still waiting on a check from my temp job to come in to spend lots of money, so I can't just buy a whole new computer right now unless I find my mother in a really really good mood (lol).

[Shuemue]

If you're lucky it was just your power supply. Grab a spare from somewhere and test that first.

[ismarc]

Powersupply, bad video card from overheating (recently ran into this, video card died and because of the way the chip shorted, any board it was in wouldn't POST), processor overheated.

I'd suggest the following test to try and narrow down what the problem is without having to crack the case open and take a look.
1) unplug the power cable from your computer for at least 8 hours.
2) plug the power cable back in, let sit for 2 hours
3) Make sure that the power switch on the powersupply is ON (may not have one)
4) hit the power button.
5) listen/watch

If it's device related, you'll probably get a green light of some sort on the front, maybe a weak whine from inside as it tries to start and fail. If it's powersupply, you shout get absolutely nothing.

Now for the complications. If you blew your powersupply, there's probably a reason for it. If it's temperature, your entire case isn't ventilated well enough and you're likely to have other chips failing soon. Also, depending how it failed, it could have taken the motherboard with it.

It's rare to damage the processor to such an extent that it is unusable. The system I play FFXI on had a full cup of coffee (including the cup) dumped into it while it was laying sideways, internals exposed, and turned on. The only thing that needed replacing was the video card because it got a hairline crack in it when the cup physically struck it. I've also had an oldschool overclocking (swap oscmod and change fsb jumpers) go horribly wrong and everything survive without a hitch.

Typically if it's CPU failing, you'll be able to start the system and get it to post, or at least start to and have random lockups/errors/reboots/etc.
If it's motherboard failing, you'll get presence of power but fail to post (or the same symptoms as CPU failing)
If it's power supply, you get no power

[Eaglestrike]

If you're lucky it was just your power supply. Grab a spare from somewhere and test that first.

I love you Shuemue <3

Replaced power supply and it's working again. Stupid of me to not have thought of that, heh.