Sorry, but no, just not possible. avast! doesn’t make false positives on digitally signed programs and i know for sure that Mozilla Firefox is digitally signed because i’m using it. avast! also doesn’t even have a feature to delete anything on as large scale that would erase all of the games. Unless the “games” are limited to some sort of browser add-on in which case it might delete them after cleaning browser and in which acase all browser data got wiped out and not the actual browser. Not sure what might have happened with MBAM, but for the other two scenarios i feel there is really something we don’t know yet…