Once again, many thanks for the advice, all.

I was just going to tack on a note re bookmarks.html, and you beat me to the punch.
I've been saving sequential versions of that file in Mozilla over the years (just in case of a case).
Since my version of Mozilla (1.0.1) is just an early version of Firefox, would be safe to say that I could just directly replace (ie, import from Desktop) the same file in the newest version of Firefox, which I'll have to download anyway?