Some more information may help us to make a suggestion.
Your operating system, what version of avast you are using (free/pro/AIS/Premier), latest version number 2015 10.2.2218) ?
What is your CPU and how much RAM ?
Do you have any other security based applications do you have, AV, anti-spy/malware, firewall, etc. ?
I don't see any issue with the right click with the latest version of avast and what security applications I have installed, see the signatire below my post.