Screen goes black and crashes when playing movie

[bsavery]

So here's the situation. I have an ATI 4850 video card, running in Snow Leopard 10.6.2, QE/CI, everything working fine. I used the graphics enabler and added the device id to the ATI4800 kext. Fine everything works.

 

Now the problem is that whenever I play a movie, any old mpeg, avi etc. The screen goes blank and as if the display was disconnected, and the system crashes. Sometimes instead of a black screen I'll get a multicolored vertical bars type {censored} covering the screen.

 

Any ideas?

Thanks!