Your update popups indicate there’s an update available for my (free) version. This is hogwash! I’ve stopped checking them as it’s never been an update for the free version yet, always just an annoying sales attempt to get me to UPGRADE to a $$$ version. >:(
Of course all that assumes I’m not missing something which I think I may have done once years ago, in which case I’ll retract it! ;D
What exact version of avast do you have installed ?
2014.9.0.2021
You have an out dated version of avast? Uninstall it via add/remove and follow the instructions. Once that has been done, use the avast uninstall utility and run it in safe mode and follow the instructions. After that install the latest version of avast 2015 via avast website and once it gets installed it will do a quick start up scan and after it has been finished do a manual reboot of your computer and register your copy of avast. Registration is free and you will only have to register once every year.
Note: There is an new version of avast and currently it is in RC2, the final version will be released soon https://forum.avast.com/index.php?topic=166883.0
Thank you both. 
Your welcome