The symptoms include:
- Complete loss of audio
- A red cross over the speaker icon in the system tray (bottom right corner) area of the screen.
- Unresponsive navigation of the Windows Control Panel causing explorer.exe to hang.
- Inability to start the 'Windows Audio' service with the error message Error 0x800706cc: The Endpoint is a duplicate.
- Inability to start the 'Network List' service with the error message Error 127: The specified procedure could not be found.
- One or more system files in AVG quarantine (this can vary).
I was sceptical at first, but started the 'repair' section of the program running with its default options ticked and left it to process overnight. After about 8 and a half hours it finally finished, and on restarting the computer I was amazed to discover that the sound was now working again. Whatever it was doing it all that time remains a mystery, and I have no idea what file or registry key was preventing the audio service from starting. If anybody knows, I would be really interested to hear from them.
Unfortunately, the problem with the unresponsive control panel remained. After examining the event logs, I found that it was caused by a faulty 'Network List' service which would refuse to start with the message Error 127: The specified procedure could not be found. Disabling the service seemed to restore normal operation, but I wasn't sure what the consequences of leaving it disabled might have been.
After a lot of trial and error, I was able to finally repair the problem by extracting the registry key that controls the 'Network List' service from a working computer and then importing it into the computer with the problem.
Key for the 'Network List' service:
After a reboot, the service started without error and the Control Panel worked normally.
To fix this on your own machine, download the file 'netprofm.reg' from the following link:
Once downloaded, double click on the file and accept any warnings that appear. This will import a working 'Network List' registry key and it will automatically replace the faulty version. After restarting the computer, the Control Panel should be back to normal.