I organize my game library the Totalbiscuit way, essentially putting everything on Steam. The problem is that I want to put the CD versions of all of them on it & the only one I can do it with is the floppy version of the first. The question is, does anyone know how to add the CD versions of all of them to Steam?

You can always create a shortcut file for a game (a *.lnk file, just like most icons on a common Windows desktop), and then add this shortcut to Steam. So if you have a desktop-like shortcut for that particular version, or if you can create it, then your problem should be solved.