Half the screen is distorted

[swanksta]

I'm using Vistax64 and the new 181.20 WHQL drivers.

Half the screen appears distorted, almost as if I were overclocking the video card too much and experiencing anomalies.

Also, I read this demo is playable. The demo launches into a benchmark, and even if I press escape and start to navigate the menus, the benchmark closes within seconds with a result window.

edit: the entire screen now appears distorted. as if the screen were made up of giant centimeter-long pixels.