You didn't mention what Operating System you are using. If you are using an XP system, try resetting the DMA. Go to Support Suite and download the One stop DMA resetter. The download is on the right side of the page. After downloading it, double click on it and follow the prompts to reset the DMA. Keep this tool as you may need it from time to time, even if it doesn't help with the current problem.
Does this problem occur while any other applications are running? Can you try the game in a different computer?
What happens to the screen when the problem occurs? Does the screen go black, or just freeze up? In an [attempt] to further rule out heat, try runing the game while the cover is off the computer. Also, blow out any dust, etc. that may be inside the case. Also, try running a fan on the computer to help disapate heat. If it is a tower case, it can be safely placed on it's side, vents facing up to help disipate heat.
Hope something here is helpful.
When I play games, sometimes my Hard Drive will turn off and then 3 seconds later turn back on again, Windows does not crash and everything still runs fine there after but sometimes it can do this twice in succession.
My Hard Drive is a Western Digital WD2500JS 250GB and it is fairly new, I only got it new about 6 months ago.
These are the things I have done with the HDD so far:
1. Made sure my power supply is producing enough juice (it is)
2. Checked all of the cables (they are all tightly fitted)
3. Took a few temperture scans, the tempertue is normal and should not be enough to overheat the hard drive, plus there is a small fan cooling the hard drive too.
4. Downloaded the WD Diagnostics tool and did an extended scan (it said everything is fine)