Hello fesee just in case you may have missed this about using old version of avast. Read this https://blog.avast.com/2015/05/06/support-for-older-avast-windows-consumer-version-will-end/
You got only until at the end of this month to use an old version of avast. After end of this month avast will drop support and you must install the latest version of avast to continue to protect your computer from malware and receive continued support