I am new to the concepts of ubuntu so this may make me sound stupid but I really want to know: IS there any way to remove all the user-installed programs and settings and set the server back to a "new" state like right after an install? I'm new(er), so I experiment a lot, make mistakes, and learn but that often has me reinstalling ubuntu to get a "fresh slate" and backtrack my issues.... is it possible? (this question is about ubuntu server software and not the desktop versions)
Not really, no. I always just go for the fresh install option, things tend to go wrong upgrading to a new release from an existing system. I imagine there's something drastic you could do with dpkg, but I wouldn't go down that rabbit hole.