Windows XP comes with a built-in wizard/troubleshooting guide that can help you solve audio problems.
1. Go to the Start Menu and open the Control Panel
2. Click on Sound, Speech and Audio devices.
3. To the left in the window you should now have a Troubleshoot section, click on Sound to launch the guide.
4. Follow the instructions given in the guide.
See also related article on how to reset your audio hardware to help solve problems.
See also related article on how to change your audio hardware acceleration to help solve problems.