Okay, the first thing I see when I look at those temps is the video card. For a 6800, the idle and load temps are both too high. I have a 6800GS in one of my systems, and it idles at 42C - 46C. So I think we can confidently say that your video card is getting too hot.
Your options:
- Buy an aftermarket cooler.
- Get a replacement card.
For now, do you have another video card you could put in the system? Even if you could borrow one from a friend. Try another card, and see if you get the same freezes.
PS - Check your private messages.
