Same problem here. This has happened to me twice in the past month. The second time, I actually got the red X in the avast icon in system tray. I also got an avast screen that said avast had stopped and offered two buttons, a 'fix' button and a 'start' button. I tried both and they made the computer hang. I managed to end the processes.
I tried to repair, but when I opened control panel, there were no icons!
I tried to reboot, but the computer would not shut down.
I finally hit the reset button on the computer and rebooted. I was then able to do a repair through control panel and somehow mysteriously, able to reboot. That was yesterday. This morning, booting up, all seems well.
It seems like the second update yesterday caused problems for me?
Scans with avast, MBAM,and SAS showed nothing.
?