I finally got a reply from Gigabyte (submitted on Sunday - answered on Wednesday afternoon). Their directions worked.
No one has answered this so I'm posting the Gigabyte reply for the benefit of others.
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If system has any PCI device temperately remove them first then reload realtek HD audio driver by follow procedure below:
1) go to windows device manager open system devices
2) Uninstall Microsoft UAA Bus Driver for High Definition Audio, if item can not be uninstall , select disable it first then Without restarting back to system devices uninstall the Disable Microsoft UAA Bus Driver for High Definition Audio should be ok to uninstall
3) Restart computer , on restart system should automatically reload the driver for the Microsoft UAA Bus driver system will then pop up driver wizard ask to load the High Definition Audio device ,close driver wizard restart computer
4) On restart driver wizard will pops up ask load driver for the High Definition Audio device again , close wizard manually open gigabyte driver CD from CDrom drive go to audio folder open realtek folder click on the realtek HD Audio driver setup file install driver, after driver complete restart system realtek HD driver will picks up and works .
If still has difficulty to follow instruction please log on this web it has images instruction: