My daughter's XP machine started losing its mind over the weekend (running very slowly and behaving randomly), and as part of my attempt to fix things I managed to lose the NTFS partition on her hard disk.
Then I found TestDisk , which did a great job of copying "lost" directories off the hard-disk, as well as recovering the partition.
Highly recommended.
PS: Boo-hiss at GParted that messed up that partition table in the first place :-)