If you do an "upgrade" install that is in effect installing the new
WinXP over top of the old Win98, so no you wouldn't lose anything.
HOWEVER, this is usually not a Good Idea. It's always better to clean
install your operating system; i.e., format the hard drive and start
fresh. In any case, you need to BACK UP YOUR DATA first because Stuff
Happens. It's also a good idea to run the XP Upgrade Advisor first to
be sure your computer, etc. will work with XP. Get it from MS's site.
