Hi,
To reinstall the audio driver and update to the latest version. In the meantime, you may have a check with hardware troubleshooting.
Open the Hardware and Devices troubleshooter
http://windows.microsoft.com/en-us/windows7/Open-the-Hardware-and-Devices-troubleshooter
If it is a hardware issue, you may contact manufacture for assistance.
Ivan-Liu
TechNet Community Support
