Avast problem not fixed by system restore

I’m helping a friend with a Windows 7 laptop (HP Pavillion). He ran into some problems; I don’t know everything he tried, but at some point he was trying to run system restore and it said he needed to shut down the anti-virus (Avast). But when he tried to start the Avast controls he got errors.

They include “Unable to start file system shield. Shield unreachable.”

“Current status: unsecured… use the fix now button.”

The “fix now” button does nothing… just no response.

“Urgent: avast service is stopped. The avast anti-virus program has been stopped, or is an inconsistent state. Please restart.”

Button to restart the avast service: first gives UAC for permission, you hit yes, and then nothing further happens.

When I got there to help him, I showed him that we could do a system restore in safe mode. I thought this was going to work–we restored back to a date two months before all the trouble started. But Avast is behaving in exactly the same way!

Try a repair of avast then reboot, repair via programs and features - double click avast and scroll down to repair and ok.

For a repair of avast. Windows, Add Remove programs, select ‘avast! Anti-Virus,’ click the Change/Remove button from the pop-up window, scroll down to Repair, click next and follow.

and also

important: any preinstalled or previous used AV must be removed before installing avast
it is also recomended to use a removal tool to clear any leftovers

run and reboot - Uninstallers for Security Software
http://thewebatom.net/uninstallers/security-software/