STB TNT nVidia 16MB PCI Video Card and Windows XP - not compatible?

Hi,

I have a Dimension XPS T500 that was running Windows 98 Second Edition. My original video card is the STB TNT nVidia 16MB PCI video card.

I upgraded my system to Windows XP Home edition. It seems that my video card is not working correctly... the DVDs do not play well, I get choppy video and audio.

I could not find a driver upgrade for my video card anywhere. What should I do? How can I make my video card work properly? Have you encounter this same problem?

Thank you,

Carlos