A:Please refer to below steps to reinstall Realtek HD Audio driver:
1.Enter into "Add or Remove Programs" and remove "Realtek High Definition Audio Driver"

2.Disable all "Microsoft^® UAA Bus Driver for High Definition Audio" in Device Manager first

3.Then uninstall all "Microsoft^® UAA Bus Driver for High Definition Audio" from the system.
4.Reboot system
5.Reinstall "Realtek HD Audio driver" from Motherboard Support CD.
If you still meet this problem, please reinstall fresh Windows^® system.