don't set a new partition just delete the old partition . boot from a floppy when you get to the options hit 3 thats delete a partition . then pick 4 thats delete a non dos partition . delete the partition and get out . don't make a new partition . take the floopy out and reboot with the xp cd in . it will act like it is a drive that is brand new and make a partition and format it .
make sure u have all you want backed up before u do this