I had recently switched from dual monitor configuration to the single monitor. The last time Avast 4.8 Home Edition was running, its main window was running on the extended monitor. Now that I have a single monitor, it starts ok but the main window will not show up on the single monitor. As a result I cannot perform any scans since taskbar icon does not have any option to initiate any scans from it. Can you help me. My video card does not change (Sapphire RADEON X1600 XT). Just monitor configuration.
Can you try to repair your installation?
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair).
If this does not help, can you uninstall / boot / install / boot again?
Tried it. Did not work. I will try to restore my previous configuration (dual monitor) and see if it will work. If not, then I try your advice on reinstalling.