if you know your video card type ( you can find it from right clicking on your My Computer and clicking Properties. Then selecting the Hardware tab and click the Device Manager button. Finnally expand the Display Adaptors section and see what your video card is ). if it is nVidia or Ati, you can get their drivers from www.nvidia.com
and if its not either one, try searching www.google.com
for the card mfg's site.