Given that your rig is running over 80 degrees (most likely C, I've never seen a program with a default setting of F), you need some serious cooling power, and NOW.

The first step is obviously to check that all your fans are running. This may involve opening the case, but you won't have to touch anything. Also, provided you are VERY careful, you do not need a grounding wire to handle your components for short amounts of time. I wouldn't particularly recommend it, but you can ground yourself on any grounded metal surface; I typically use my kitchen sink.

The second would be compressed air. Trust me, this is a must. I tried to use a vaccuum, didn't get the job done (even though it looked fine) and went over the same areas with compressed air. Dust everywhere. Be sure to take it outside when you spray it.

The next step would be to check that your CPU has the correct layer of thermal grease. Note that while it's very difficult to have too little of this stuff, it's quite easy to go overboard! Make sure you've got some, but don't use a whole tube or you'll kill it.

The last resort is the installation of more fans. Preferably, you would have 2 outtake (blowing out) vents in the back, and two intake vents, in the front and side. However, some cases are not built for this, like mine.

As I have a badly cooled computer with a reasonable (GeForce 9600) graphics card, I'll try and find a copy of crysis and run it, and see if I run into the same problem. Cheers, and best of luck.

I had issues with cooling a long time ago, nearly burnt out my old AMD. I decided to put my most recent computer to the ultimate test; I built it during the Australian Summer, which is around the Christmas Period. If a computer can withstand the Australian summer than it's worthy of playing my games.

I'll have to try that if I take out my graphics card to clean it. But if you take out the graphics card and put it back in again, would you have to go through the hardware installation process again, or does the computer not know anything?

I tried this. Got a lot of dust out of the computer, but I still think there may be some in the heat sink. And there always seems to be a thin layer of dust on my video card whenever I open my case to clean it, and all the circuit joints make it tough to clean. I also really cant get the dust out, because it just resettles. However, I feel a lot of heat where the CPU is when it crashes. I think that the CPU is getting stressed because there isn't enough RAM. Even though I have 3 gigs of DDR3, I don't think its enough.