Is Avast unable to distinguish between its being explicitly turned off by the user (forever) and it’s having crashed? I turned it off to troubleshoot, and now I’m getting a balloon that WebRep has crashed.
What OS?
Which version of avast?
Other security software?
Try a repair. Control Panel>uninstall a program>double click “avast”>scroll to and click “repair”>reboot. 
If Web Rep is crashing in Google Chrome,
Use the following fix:
https://www.youtube.com/watch?v=S_KONTflvTk