Just to clarify something: you said you did all the necessary stuff, but was that to get it working as a workstation? At any rate, since W2K3 Server doesn't come with Direct X 9.0c I would suggest installing it, or reinstalling it if you have done so.
Neowin did a good Windows Server 2003 to a Workstation Guide which you can fine
HERE . Check some of their suggestions versus what you have done to see if there is anything that you might have missed.
- Tip