sims 2 disagreeing with video

when i try to run the sims 2, crazy stuff happens and my computer switches to software graphical rendering (ithink).
then sims pops up a dialog:

failed to find any directx 9.0c compatible graphics adapters in this system! please make sure you have a directx 9.0c compatible graphics adapter and have the latest drivers provided by the manufacturer. the application will now terminate.

probably because it just crashed my drivers ><
i'm running winxp sp2 with radeon 9550 video, and yes, i updated the drivers. two or three times.

WHAT HAPPEN ?

Have you tried re-installing the sims or checking any of the game's support forums?