white screen after installing ATI driver
 

hey to all :D
i installed mandriva 2008
but the video card wasn't installed so i downloaded the ATI driver from the main site for linux i installed the ATI and turned the 3D mood on after that i restart my computer and when the linux finsh loading i got white screen and i tried every thing but keep the white screen so i formated my pc and and back normal so i came again and install my ATI after the formating and again after the restart back white screen and i formated it again and now i didn't install the ATI card yet hehehe so plz helppppppppppppppp
thanks

and sorry for my bad english :)