No Sound with error message 'Error code 0x800706cc: The endpoint is a duplicate'. Also a red x over the sound icon on the icon tray.

Thank you so much, nothing seemed to work and not only audio but also other apps were failing. AVG should know about this. Thanks again!

I also had the AVG problem but deleted AVG when it happened, a while ago  before  I found out the problem could be fixed by the virus vault content. I re-downloaded AVG & of course nothing is there from the date it was messed up. I also downloaded some updates from this site and can't install them. My computer tells me there are updates waiting, but I can't find them and when I use the Windows 8.1 setting and click "updates," the box stays white and little spinning ribbon never goes away. There's a place where you can check a box in windows settings for automatic downloads but I try to check it and it won't take.  Thanks for any help. it's been a long time and I'm paying for music and video services that are useless without sound. 

Thank you again,    Paula

Hi,

Sorry for the delayed response.

I suggest you to follow the methods below and check if that helps.

Disable anti-virus. 

When you disable Antivirus:

Important Note: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.

For most Antivirus programs, there is an icon next to the clock in the task bar, you should be able to right click the icon and either be able to disable it from there or you can go into the options and disable it.

Note: If the issue still persists, you can turn on your Antivirus program later.

Please uninstall and re-installthe audio driver and check.

Please follow the steps below: 

1. Press Windows key + R key, type devmgmt.mscand click Ok.
2. Expand the audio driver, right click and uninstall the driver.

After uninstalling the audio driver, please reinstall itfrom the manufacturer website and check if that helps.

Do reply to us with the status of the issue so that we can help you further.

What if you deleted the virus vault when uninstalling AVG before restoring the files?