yep, saba, being there done that, but, still no bl00dy t-shirt
what you need is the
Gparted LiveCD use testdisk on the CD to restore your data, it would also be a good idea to set the disk label (to destroy any corruption) after restoring data & backing it up
Edit: i think you have a corrupt partition table
Edit: the same thing happened to me, but, i personally chose to DBAN the HDD, so, nothing could survive obviously after restoring & backing up