Media player problems
 

I have just installed a new graphics card (GeForce 6200 512MB), but now I am having problems when i try to use a media player (Windows or quicktime). They basically get as far as loading up as if the player is ready to go, but i then get no picture or sound, and the player uses 99% cpu , and i eventually have to kill the task.

Any ideas on what i can try to resolve this (apart from remove thecard??!!)
Cheers
Thommo