I recently replaced MSE with Avast. Uninstalled MSE before installing Avast.
The system tray icon turns red with an "X" The user interface shows:
YOU ARE UNPROTECTED! "Avast background service is not running"
I click start now and it's working again. Awhile later, same thing happens again.
I did a repair through Add or remove programs. No help.
I'm now in the process of uninstalling Avast with the avastclear.exe tool.
I'll reinstall MSE after that.
I'm posting this more to inform the community...If a lot of folks have this problem, it may not be quirks with individual PC.s
I'm using Avast on several other desktops with no problems, but I've had problems with this and the prior laptop.