There's a good chance I can help, but I need to know a little about your PC.
The easiest way to do that is to run DX-Diag, and send me the results.
1. From the start menu, do Start->Run
2. In the little box, type in "DXDiag" and click "OK"
3. DXDiag will run for a minute or two.
4. Click on "Save All Information" then click "Save"
5. It will create a file called "DXDiag.txt" on your desktop, send that file to me. It doesn't reveal any personal nformation, just the technical data for your PC.