Motherboard problem.

Your chipset is overheating. You need to replace your chipset fan or cooler. I have a similar problem on my computer.


1. Lower your AGP mode to 4x or 2x (temperary solution)

and

2. Replace your chipset fan or cooler on your motherboard.

And / or

3.Add more case fan.

My experience is that 90% of hardware problems are related to heat. (10% is cheap components like benq cd-rom or azen ram)