Fresh install but with any previous antivirus? OEM?
It’s not a good idea to downgrade… Anyway, I suggest an installation from the scratch:
- Uninstall avast from Control Panel first.
- Boot.
- Use Avast Uninstall for complete uninstallation.
- Boot.
- Stay off-line (not connected to Internet)
- Install again the old version: http://filehippo.com/download_avast_antivirus/
- Boot.
- Register avast (insert the registration key).
- Uncheck the programs updates (set to manual).
- Only then connect to Internet (go on-line).
- Check and post the results.