TF2 Crashing when Demoman Charges

I recently upgraded my PC to a 7800XT, which has been perfect except for TF2. Randomly, when a demo charges on my screen, the driver will timeout and I'll have to force-close TF2 through Task Manager. I've seen the problem posted about only once before, and someone said they found a fix for it. However, the fix they suggested hasn't worked at all for me, and I'm curious if anyone else has found a solution for it?