Over the years that I've been using AVG, it's gotten messed up several times.
I usually just do a re-install and that fixes it and I move on.
Before doing that, you might check in "services.msc" and see if all the AVG modules are set to Automatic and running......if not running see if you can START the service.
You might also do a System Restore (Registry Restore) to a point just before the problem started. I use that feature of windows at least once a week to fix one thing or another.
Failing that, I would definitely RE-Install AVG and take the "Repair" option during the beginning of the install.