Jimmy Brush

Sounds like your video card driver is unstable.

If you are using the video card driver that came in the box (so to speak)
with Vista, try upgrading to the latest video card driver available for
Vista from your manufacturer.

If you are using a video card driver from your manufacturer, try rolling
back to the default Vista video card driver.

Once you've done that, try running a system performance test again - this
should kick-start desktop composition. You can do this from Control Panel ->
System and Maintenance -> Check your performance rating (under System), and
then click Refresh my rating now.

- JB