i'm willing to bet it's the video card causing it.

Simply put, ATI & Maya don't mix very well, especially in versions before Maya 6.5.

With my 9800pro I had that exact issue in Maya 5, except when the computer went blank it was recovered through the 9800's VPU recover option.

Maya 6.5 is a lot more stable, thankfully, though it will still crash if you have anti-aliasing and anisotropic filtering enabled, and it wont' even start if you have vsync on.

best permanent solution would be a different vid card which is on Alias's compatibility list, but otherwise its a tough thing to give fixes for.