Remember the Systemrestore is not an uninstaller tool. It will restore the system to that point the Restorepoint is set. So if you install a tool and than an other and you want to delete/uninstall only the last one you will lose the first one too, because the restorepoint was set before the installating the first tool.

And about the false alarm thing: send them to the Avast-support, because we are only Avat user( exept the Alwillteam members of course)