I encounted just the same problem as described by clare99 in the initial post:
The Avast Icon in the status bar shows a yellow triangle with an exclamation mark. On the overview screen ("House" tab) there is a yellow field at the left side saying "Achtung - Some shields are off: Einschalten". (mixed german and english there). If I click "Einschalten" [switch on] it says (in german) that the components IM protection, P2P protection and file system protection cannot be startet.
- I found out that in the account settings no account was connected and connected it to the e-mail address again
- I have the latest version 8.0.1483 installed
- I restarted windows
- I tried restarting the Windows Service. I found it running and could restart it after confirming the alert.
- I tried resetting the database in Software updater > troubleshooting and restarted windows
- I used the repair tool from Control Panel > Uninstall/change programs as you suggested. Windows restarted again
- I performed a manual system scan (which was possible) which didn't discover any virus.
None of them helped. System is Windows 7 32 bit. There is no other antivirus software installed but there is ThreatFire, which is a heuristics program and frequently recommended in computer journals to be used together with avast (and Secunia PSI for updates) to have a round secured system. Finally I found the solution:
For whatever reason ThreadFire has locked some of the Avast components. First I removed that lock from "Global Action List" > "Locked". After restarteing windows, the problem remains but the message that the components IM protection, P2P protection and file system protection cannot be startet doesn't show up any more. I then re-ran the repair tool form Control Panel > Uninstall/change programs which finally brought it back to life again.
I hope this can help somebody out there.