I'm not sure that previous posts were very clear. One can format their hard disk to be completely empty and then load up a Win9X startup disk (to load CD drivers). At the DOS prompt, type in the letter of your CD-ROM and type 'setup.' Win XP UPGRADE will load, but eventually you will be asked for your original Win 98/ME disk for verification only, then XP UPGRADE will continue. So, you DON'T have to actually install a previous qualifying OS to load up XP clean.