I had to do the same thing recently, and as PSF says if you un-install the card in device manager and re-boot, when you boot back up it should automatically find the hardware (in XP) and re-install it for you.
You might have to make a few changes to your screen resolution and icon size etc.
After I did this I checked to make sure there weren't any updates for the drivers (there weren't for mine) and everything was fine
Use the detonator destroyer to remove all traces of the drivers.
Did you un-install the old drivers, if you did not that is what could have caused the problems.
To be sure un-install the drivers in the control panel>> do not re-boot>> un-install the card from the device manager>> do not re-boot>> run detonator destroyer then re-boot>> Windows will find the new hardware, stop the install, manually install the drivers then re-boot. Re-set the display size and resolution and hopefully you should then be ok.
This thread is now locked and can not be replied to.