Task Bar locks up Start button distorted

I have W2K Professional, Athalon 6ooMhz,128mb Ram and (2) VooDoo cards for video. I have only installed one in W2K OS.
Everything works after login, except the Task bar will lock up and the Start Button will become distorted in color. I have lookedfor updated drivers and that is why I only installed the one card in W2K OS. The other card has no updated driver available for W2K.
Thank You,
Dan