Have you ever seen annoying mouse trails all over the screen when the game options menus are displayed (it makes the menus almost unreadable)? Or a reddish background screen (the red screens at when you start the game)?
Either way, Zygodactyl's advice is good to follow. This is how I'd do it in your case:
1. Kill (close) all background programs and unnecessary processes (CTRL-ALT-DEL).
2. Made sure no device conflicts in Settings - Control Panel - System - Hardware - Device Manager.
3. Made sure Sound is installed correctly.
4. Uninstall WMP10, then reinstall WMP10; download the WMP10 standalone installer (13 MB) for free from MS here .
5. Install DirectX 9.0c and verify it is working (run DXDiag tests); download it for free here.