... i'm a linux newbie ... but i'm quite sure what my problem is....

my mother board has an ATI graphic card.... but i'm currently using another graphic card (Nvidia) .... but the auto detect keep detecting my ATI graphic card .. and i cannot remove it as it is part of the mother board...

anyway to manual set it to my current Nvidia graphic card?
heard something about disabling it in BIOS ...but i have BIO-phobia.... :P

thanks in advance
p/s : i'm trying knoppix before i get an actual linux distro :P