I have just experienced the same problem. I have an nvidia geforce 7800 video card. I thought maybe the driver needed to be updated or something. NOPE! That didn't work.
I've had the game for about a year (or more) and it NEVER crashed once. Then all of a sudden, it started this a few days ago and it doesn't work for more than 10 minutes at a stretch. Exact same problem you have.
I have a high-end system that I built myself. I have never screwed with mods or installed any of those gay cheating trainers. I have never used cheat codes or anything. Have you figured out what the problem is/was? I doubt it has to do with the video card, since nothing has changed on my system... EVER.