I suggest an installation from scratch:
- Download the latest version of Avast Uninstall Utility and save it.
- Download the latest Avast version and save it.
- (Optional) If you want, save your Avast settings for later restoration (Settings > Maintenance > Back up).
- Uninstall Avast from Control Panel (if possible) and reboot.
- Run the Avast Uninstall Utility saved on 1 in and follow the instructions. Reboot Windows in Safe Mode, uninstall Avast and then reboot in Normal Mode again.
- Install Avast using the setup saved on 2. Register your free copy or add the license key for the paid versions. Boot.
- Check and post the results.
Please, be patient, boot when it’s said to boot…