TG, there is no excuses for this lack of detection…
Can you send cool.exe and ntsysmgr.exe files for Alwil to analysis (virus at avast.com)?
Anyway, we can discuss your avast configurations…
For instance, you said, right clicking the files and scanning them. Well, you should know the differences between the Home version and the Quick scanner of avast, for instance. It’s not an excuse. Just differences between programms. :-\