I recommend you do an uninstall and
CLEAN install again. However since there may be remnants of version 4.0 and 5.0 in the machine,
you will need to uninstall BOTH versions using the Uninstall Utility in Safe Mode.
1. Save a copy of newest version of Avast (5.0.594) for the version you need and save it to your HDD:
Pro –
http://files.avast.com/iavs5x/setup_av_pro.exe2. Download the Avast Uninstall Utility, aswClear5.exe
http://www.avast.com/uninstall-utility and save it to your HDD (it has uninstall tools for both 4.0 and 5.0).
3. Disconnect from the Internet at this time.
4. Uninstall Avast through "Add/Remove Programs".
5. Boot into
Safe Mode and run the Avast Uninstall Tool.
6.
Reboot twice.
7. Clean your computer up (clean up cache, etc.).
8. Install the newest version of Avast and
reboot twice.
9. Get Internet access and update Avast definitions.
10. Register your copy or add the license key for Pro.
11. Reset your settings, if needed.
Please post your results. Thank you.