I advise you to backup all your data and settings
then perform a clean install.
Then let me point out to "Upgrades" that I advise exactly the
opposite.
Unlike with previous versions of Windows, an upgrade to XP replaces
almost everything, and usually works very well.
My recommendation is to at least try the upgrade, since it's much
easier than a clean installation. You can always change your mind and
reinstall cleanly if problems develop.
However, don't assume that doing an upgrade relieves you of the need
to backup your data, etc. before beginning. Before starting to
upgrade, it's always prudent to recognize that things like a sudden
power loss can occur in the middle of it and cause the loss of
everything. For that reason you should make sure you have backups and
anything else you need to reinstall if the worst happens.
If you insist on trying to upgrade win2k directly to XP...
you still should backup your data first.
Absolutely. I completely agree with that, as I said above.