More things to try
1.
Open Device Manager by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Maintenance, and then clicking Device Manager. Administrator permission required If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
2.
Expand the Sound, video, and game controllers section.
3.
Right-click your sound card in the list, and then click Disable.
If disabling the sound card resolves this issue, contact your computer manufacturer for more troubleshooting steps.
2.
http://www.gremedy.com/download.php
3.
check you have the latest Vista service pack