Sound advice from Craig there, as usual. I go a step beyond. When I'm going to install a new version of Mach4, I rename the Mach4Hobby folder to something like Mach4Hobby_4322. Then I install the new version which creates a new Mach4Hobby directory. I then open two explorer windows and copy over my license, profile, screenset, plugins, docs, and maybe modules (I don't have any custom modules currently, tho'). If anything goes haywire, I can just rename folders to get back.
I go a step beyond and whenever I'm going to try something new, I copy the entire Mach4Hobby folder off to a different drive or network location for safe keeping. If I think of it I do this once in a while just for extra safety to always have a known, working copy of the entire Mach4Hobby directory I can simply copy back to C:\. Might be just me, but I fantasize that I NEED the machine to work so I do belt and suspenders!!