Which PC to try FC2 on first?

[beartooth]

What I call my backup machine or my map machine, according to use, is an
athlon a couple years old, with 1.5 GB of RAM, a 14.5GB hard drive running
Windows XP/SP2 for GPS/topo map stuff, and a new 80GB hard drive (of which
45 GB are a /shared partition, accessible to both drives), running FC1.
I'm a little hesitant to upgrade it, for fear of somehow making XP even
worse than it already is.
                                                                                     
(I have a tale of woe about XP and the new GPSs, but I'll save that --
except to say that I hosed it, and had forty hours' work getting XP back
to where I had had it.)
                                                                                     
        The other is a 1998 pentium2 with either 256MB or 384MB of RAM
(I disremember), and two hard drives, a 20GB and a 30GB, running FC1
jointly on both; I plan to make it the LAN server, when I get as far as
setting up a home LAN. Meanwhile, it's essentially a backup to the backup:
tweaked the same way as both my main (FC1) and my backup (FC1) machine,
and running the same applications when it runs at all.
                                                                                     
        I'd prefer to try an upgrade rather than a clean install,
just because, if I get away with it, I'll've spared myself the tedium of
downloading and installing which a clean install would require to get it
into the shape I want to run.
                                                                                     
So which machine would you try FC2 on first, and why? Or is a clean
install the only way to get from FC1 to FC2 -- still? (I recall people
here saying so when FC2 was newly out.) And in either case, how do I make
sure when I get to the map machine that FC2 doesn't touch the XP part?

-- 
Beartooth Implacable, Linux Evangelist & Gadfly
neo-redneck, curmudgeonly codger with FC1, YDL4 -- & XP
Pine 4.62, Pan 0.14.2; Privoxy 3.0.1; Opera 7.54, Firefox 1.0
Bear in mind that I have little idea what I am talking about.