It's a little late, since you're running XP, but if you had created another partition (D:) on your new, monster hard drive you could keep most of your documents/files on that. If you ever need to re-install XP you don't have to worry about saving your files. (I usually did, just in case, anyway.) I'll refrain from giving detailed instructions, unless you want to give it a try.

PM - who upgraded to Windows 7 from XP just before Thanksgiving and find I rather like it!