I have avast! 4.7 free version. I followed the instructions from support/FAQ:
If the service cannot be started, your avast! installation might be corrupted. Try repairing the avast! installation: click START -> CONTROL PANEL -> ADD/REMOVE PROGRAMS -> avast! Antivirus -> CHANGE/REMOVE and select REPAIR.
Cannot select REPAIR. When I click on CHANGE/REMOVE, nothing happens. No REPAIR option is displayed.
I am using a router (Netgear). Another FAQ/support said to change the proxy settings (I am using automatically detect). I do not know what setting to list. I know my IP address, but not which port to use. Thanx.