Your fdisk output shows an unformatted, non-partitioned 82GB hard drive. If this is the internal drive you want xp and Mint on, install xp first then install Mint. After installing xp, run the fdisk command again so you see which partition is xp (ntfs) and don't install Mint to the same partition. When you get the option at the end of the Mint install, it would be best to select install Grub to the master boot record which should be the default. It's a lot easier than trying to boot both from xp.