Crashing, weird video pattern

My computer just started crashing soon after powering up. I can sometimes get to the desktop, but before it'll crash- and the display becomes a weird tiled pattern containing a very small section of the current screen (repeated hundreds of times). This pattern holds, not moving, until I hard restart.
Sometimes it will crash this way during post.

This morning I was fiddling around with the Creative X-Fi control panel, adjusting surround options and the Crystalizer. Then I shut it down, and the first crash occurred when I booted it up later. Could it have something to do with this?

Windows XP SP2
Asus A8N-SLI
Athlon X2 4200
2GB DDR400
250GB Seagate system drive
GeForce 6800GT
Creative X-Fi

Thanks in advance!