i wouldnt use fdisk with a hdd over 60gb - apparantly, it doesnt always work as well with anything bigger (or is it 70gb?)
if you've got a hdd already in the pc, use the disk management facility in administrative tasks > computer management
right clicking the drive will allow you to set up partitions. when partitions are made, it will ask you if you want to format it/them and also what file system you want to use.
if you dont have a hdd already in the pc, just boot from your XP cdrom, and set it up in there - that supports the big hdds afaik