You will need to by the FULL versions of either Pro or Home. You could a
repair reinstall of XP Pro over top of the "installed" version. As for
Home, you will need to do a clean install. This erases everything!


"MSS" wrote in message
news
I have XP Pro Version 5.1 running but I do not have the original XP disk.
I
tried to install the various upgrades via download as well as with a
service
pack 2 disc. I get an error message that I have an unregistered copy of
XP &
therefore can't do the upgrades. Can I purchase & install XP PRO as an
upgrade or do I have to buy the full program? Also, what if I want to
but
a lower version of Windows rather than XP Pro.