are you using a 3dfx 1 based card? I had exactly the same problem..
dx6 drivers and monster1.9 drivers etc but had the problem. The game
has a 3dfx directory with a file containing some (older) drivers. I
loaded those and the graphics are fine. (No problems with other games
either. As a bonus the static I was getting thru the sound card
SBLive Value has been eliminated from my system also)
tob