-- Windows XP --
1. Click Start then Run.
2. Type in dxdiag and press enter.
3. Click on Save All Information and save it to your desktop or where ever you like.
4. Locate dxdiag.txt on your desktop or where ever you saved it and attach that to your email.

-- Windows 7 / Vista --
1. Click Start and type Dxdiag in the search.
2. Click on dxdiag.exe.
3. Click on Save All Information and save it to your desktop or where ever you like.
4. Locate dxdiag.txt on your desktop or where ever you saved it and attach that to your email.