Help me, WoW problem D;

[Gstar]

Okay, well, I have tried to run WoW and play it like a mofo BUt,
when I login and get set and everything I start to walk about about 20-40 steps into the game It freezes and kills my pc totally making me restarting the shit over.
So anyways, I thought it might have been my Graphics card which is a:
ATI RADEON Xpress 200 Series.

The new one I bought is a:
EVGA(Nvidia) GeForce 8400 GS

but when I disable the ATI one my screen shrinks and it renders WoW unable to play, I need some fuxxing help here. I'm like dieing to get back on wow.

[Gstar]

/bump D; (filler)