I haven’t been using avast for long enough to know its interface perfectly. But I had been using AVG for quite some time before switching. The avast program doesn’t seem to do full system scans on a scheduled basis like AVG. Instead, it is a resident scanner - scanning files as your system tries to access them.

To get some of the “scheduled scan” capability that AVG has, I have begun to use the Avast Screen Saver, which does a system scan when your computer is not in use. One of the wishlist items I’ve suggested is adding the results of this screen saver scan to the main console, so you get a feel for when the screen saver system scan was last completed.