Download and install GLDirect. It makes OpenGL games use DirectX instead.
You may need to download DirectX 9. Don't worry, it won't mess with any of your Direct X 10 stuff.
Make sure that GLDirect has rendering set to your Video card rather than software rendering.
Here is the link.
ftp://ftp.scitechsoft.com/gld
After install, click the free-gldirect-code.txt. The product used to be shareware, now they have released it for free. Got Jedi Academy running on Vista with this.