Hi,
I would suggest you to follow the steps mentioned below to resolve the issue:
1. Run the Fix It mentioned below and check if that resolves the issue:
http://support.microsoft.com/mats/hardware_device_problems/
2. You may also like to try the Fix It mentioned below:
http://support.microsoft.com/mats/no_sound/
3. I would suggest you to uninstall and reinstall the driver and check if that resolves issue. Download the driver from the manufacturer’s site.
Hope this helps.

