ok so I can give a lot of information about this... I'm pretty good with computers but this seems to have too many possibilities, I want to narrow it down.

First thing, what actually happens:
I will start up a game, depending on the game this crash will happen at different times, for dawn of war it happens later on and for black and white 2 it happen during the intro cut scene. Then my computer will enter sleep mode, sound will glitch out after a few seconds and then a force power off (hold down power button) is required, the machine wont respond any other way. The whole time thing leads me to suggest that it is a temperature thing.

Second thing, OCCT tests:
I ran a cpu test and my cpu is fine, during the cpu test my gpu was roughly 70-72 degree celsius. I then ran a gpu test, soon after myu computer crashed and entered sleep mode, this also suggests heat problems, but I do not fully understand why it is crashing here because no graphs were saved.

Third thing, what happened before:
I recovered from a rrod by formatting my c drive, my d drive was left untouched, the only things ever put on my d drive are fraps and hypercam recordings and rendered videos.
I first experienced this in minecraft while running a server and playing in it with a friend, it didnt occur for a while after so i wrote it off.
For a few days before this became serious my computer was derived of being turned off due to my insomnia, it was really bad and I couldnt sleep and my computer ended up being left on for about 5 days (3 days awake, 1 day asleep then another day playing rs with some friends) before I turned it off.

Ok, so I have a feeling that this is heat related, but some incidents suggest it is possibly driver related, so if anyone can give me a few links of some drivers that might help (or drivers that could be uninstalled to help) then please share them, I do not want to have the void the warranty on my pc by opening to find out it is a software issue not hardware issue.

Also, a program called game booster, from what I've read about it, it should help lighten the load on my cpu and gpu, but I'm not sure whether to use it, it says it will shut down unnecessary programs for gaming. Can anyone clarify that this program is safe to use?

Here are my computer specs:
windows 7 64-bit
1gb nvidia geforce gt320 graphics card (I've seen similiar problems to this with GT series cards)
intel core i5 processor 650 3.20GHz
4gb ddr3 ram
500gb c drive and 500 gb d drive

My nvidia drivers are up to date

(sorry for any poor grammar or spelling in this, its a lot to type :/)

This Sunday I will be taking the side panel off of my pc and removing all the dust, I am getting a new desk unit that day (this current one has a damaged slide out shelf) so it will fit in perfectly, I will post again whether this problem persists. If it does and I don't see anything out of the ordinary inside the pc then I will assume it is software related, but I have no idea what kind of software would help or isn't helping whichever it may be.

I ran a cpu test and my cpu is fine, during the cpu test my gpu was roughly 70-72 degree celsius. I then ran a gpu test, soon after myu computer crashed and entered sleep mode, this also suggests heat problems, but I do not fully understand why it is crashing here because no graphs were saved.

Ok, so I have a feeling that this is heat related, but some incidents suggest it is possibly driver related

You need to ensure it is not heat before dinking with drivers. Drivers don't just go bad - if was working fine before, the driver should be fine. The only driver I might consider updating would be the graphics driver.

Is the interior of the computer free of heat trapping dust? 70°C is too high for most CPUs. The CPU itself could be get unstable at that point, or the BIOS could shut it down based on a threshold set in the BIOS Setup Menu?

If clean, blast a desk fan in to the open side and see if crashes. While at it, inspect the capacitors surrounding the CPU socket for leaks and bulges. These are tall soda can shaped devices. Look for dried white to dark-brown foam on the tops or bottoms. Bulging is an indication the pressure relief points are about to split allowing the electrolyte to leak.

Have you scanned for malware?

Originally Posted by Digerati

You need to ensure it is not heat before dinking with drivers. Drivers don't just go bad - if was working fine before, the driver should be fine. The only driver I might consider updating would be the graphics driver.

Is the interior of the computer free of heat trapping dust? 70°C is too high for most CPUs. The CPU itself could be get unstable at that point, or the BIOS could shut it down based on a threshold set in the BIOS Setup Menu?

If clean, blast a desk fan in to the open side and see if crashes. While at it, inspect the capacitors surrounding the CPU socket for leaks and bulges. These are tall soda can shaped devices. Look for dried white to dark-brown foam on the tops or bottoms. Bulging is an indication the pressure relief points are about to split allowing the electrolyte to leak.

Have you scanned for malware?

I have used norton and advanced system care 4, no malware was found.
The cpu was not at 70 degrees, it was the gpu, and I know for a fact that the gpu has an auto shutdown when it hits 105 degrees. but I couldnt understand how it could rise in temperature so quickly.
My graphics drivers have been updated with no effect.
I will be able to report anything strange on the inside on sunday, but as for dust on the back vents and the back fan, there isn't any.

during the cpu test my gpu was roughly 70-72 degree celsius

Sorry. 70°C for a GPU is fine. Note if the fan suddenly stops for some reason, temps can rapid shoot way up.

I will be able to report anything strange on the inside on sunday

Sounds like a plan. Keep us posted.

Ok, so my computer seems to be working now, I got through an entire game on monday night combat monitoring the temp as usual and it stayed steady at 70-72
I'm gonna keep monitoring it and I'll post in a week if alls well, if my comp crashes again I will post saying so. thanks for all your help

Computer has worked fine all week, making more noise than usual so I'm guessing some dust was making the gpus fan stick... which would explain the temp being normal and why it would randomly shut down

Sounds good. Thanks for the follow up. And remember, fans suck in heat trapping dust almost as well as they do air.

I hate how the same day I say my computer's working fine the problem reoccurs... Performance drop is still there and it crashed while playing retribution, I had it set to medium specs and it still crashed. I had hoped that the problem was gone but I guess just cleaning my pc was too easy of a fix...
There must be another problem with my gpu... this is rather annoying

But it was working better so if it was cleaning and not just a coincidence, then maybe heat is still the issue. I would blast a desk fan in there and see what happens.