Did you do a repair of avast via add/remove? If you have done that and it didn’t solve it. Uninstall avast via add/remove and follow the instructions. After that download and run the avast uninstaller utility and it will ask you that this tool will run your computer in safe mode automatically, click yes and follow the instructions. Finally, install a fresh copy of avast and after the installation has been done it will do a quick start up scan. Once done, restart your computer manually and register your copy of avast.
