|......."f you're performing a clean installation of XP Home or Professional using an Upgrade CD, be sure to have your qualifying media handy. This can be a retail Windows 98, 98 SE, Millennium Edition (Me), NT 4.0 or 2000 CD-ROM or, in some cases, a Windows CD that was supplied with a new PC. Note that "restore" CDs will not work, however, and most Windows CDs that ship from PC makers are now restore CDs."|
You don't have to load the original OS, you just need it handy to complete the installation.