Computer problems. Please help.

So, a few months ago when I was playing a game, though I don't remember which one, maybe Crysis, maybe even just the first Deus Ex game, but what happened was my brothers computer just turned off, and only the fan and power light was going. The power button/light just flashes on and off. Now, it goes off more frequently, and it doesn't matter what we do. It can either take a matter of seconds (though more rare), minutes, or even maybe an hour if we're lucky. Is this a power supply problem, a hard-drive problem; is the computer working too hard? 
 
What is it? As I type this right now, it's doing it. I was playing Starcraft 2, and during one of the earlier cut-scenes in the game as I was playing campaign, it just went off. Not that it'd help, but I just left for about five minutes, got a vacuum and just vacuumed the dust out of all my systems including the PC. Every time the thing goes off, the only way I can get it to go again is to unplug the computer, and sometimes it doesn't work the first time, so I have to unplug it and plug it back in again. Any help be would be great, thanks in advance. 
 
I will admit, we need a new computer, 'cause this one is not good for gaming... it's kind of sad.

...

Although I would recommend you heading over to TomsHardware for this type of stuff, it seems either your PSU is faulty (most likely) or you are overheating and that is causing the shutdown.

I'm going to says it's overheating shutting itself off to save the cpu.

I'd start by monitoring the temperature of the cpu and video card.

@NTM said:

@salad10203: @Kidavenger: Interesting, alright. Thank you. If it's the overheating, how would I fix that? A new fan or something?

If you would have fixed the problem right way a new fan might have helped on your cpu or gpu. You seem to have been still using the computer for some reason so the damage is probobly done. Buy a new cpu or video card once you troubleshoot which one is actually bad.

Try to turn down the overclocking on you video card, if that doesn't work, go to best buy and buy another card and see if that helps. At best buy its pretty easy to return cards if you have all the parts and it is within seven days.

@Joker369 said:

Try to turn down the overclocking on you video card, if that doesn't work, go to best buy and buy another card and see if that helps. At best buy its pretty easy to return cards if you have all the parts and it is within seven days.

After reading his opening statement and looking at his computer stats do you really believe he overclocked anything?

@Joker369 said:

Try to turn down the overclocking on you video card, if that doesn't work, go to best buy and buy another card and see if that helps. At best buy its pretty easy to return cards if you have all the parts and it is within seven days.

After reading his opening statement and looking at his computer stats do you really believe he overclocked anything?

@NTM said:

@salad10203: @Kidavenger: Interesting, alright. Thank you. If it's the overheating, how would I fix that? A new fan or something?

Get some thermal paste take the heatsink off, clean it well, apply the paste and reinstall. make sure it's actually overheating first though, so many things it could be, overheating is just the usual suspect.

@Kidavenger said:

@NTM said:

@salad10203: @Kidavenger: Interesting, alright. Thank you. If it's the overheating, how would I fix that? A new fan or something?

Get some thermal paste take the heatsink off, clean it well, apply the paste and reinstall. make sure it's actually overheating first though, so many things it could be, overheating is just the usual suspect.

I guess he could try that but from his other statements he seemed to have been running his pc a lot without fixing the overheating issue. The damage is probably done by now and the part/parts most likely need to be replaced from long term thermal damage.

What the hell are you talking about? You cut those specs in half and that's what I have. And I run things just fine.

@Titus said:

What the hell are you talking about? You cut those specs in half and that's what I have. And I run things just fine.

No... what are you talking about?

I would check the power supply, a lot of weird hardware problems can be traced back to the power supply