I can only answer your secod question: You don´t need to do a from-disc install to have a second (or thrid, fourth...) copy, just copy the whole RTW folder (might take some time, for me it´s usually about 15 minutes) and there you are, it´ll be named "copy of Rome - Total War" and you can rename it to anything you like. Of course, you´ll have to do the desktop shortcuts yourself and I don´t know how to get start menu entries for the additional copies, but that´s all there is to it.

I hope that, at least, was helpful.