meddog,
I just switched from GF4-440 MX 64 to FX 5200 Ultra 128. Plays AHII great now, and AHI too.
As bokko said, try removing all Nvidia drivers, reboot, then install newest Nvidia divers.
After that, re-download and install Direct X 9b. Even if you have DX-9 now on your computer, do it again.
Should run like a charm.