Hello is thsi the free or Paid version?
Try a fresh install.
1. Download the latest version of Avast! Uninstall Utility
and save it to the desktop.
2. Download the latest avast! version and save it. This is the free one ... Version 5.http://www.avast.com/free-antivirus-download#tab2
3. Uninstall avast from Control Panel,Add Remove(if possible). If, for any reason, you can't run it, try booting in Safe Mode
and doing it from there. Reboot after that.
4. Run the avast! Uninstall Utility saved earlier. If, for any reason, you can't run it, try booting in Safe Mode and doing it from there. reboot after you've run it.
5. Install avast! using the setup saved in step 2. Reboot.
6. Register your free copy or add the license key for Pro.
7. Check and post the results.