Right click on "my computer", choose "manage", go into disk manager and right click on the drive you want to format. You don't need fdisk in windows xp either. You can partition with the disk manager as well. If you want to prepare the drive for a new OS install, most OS's now have the option during setup to format the drive, though it's entirely unnecessary if you just want to reinstall xp. Xp also has the option to delete the old windows if you attempt to install it on the same drive / partition/ folder.