Sorry but if niether Ubuntu or Parted Magic can see any partitons with gparted and Test disk can not see any partitions or evidence of partitions I think it is likely that the disk has died.

I think the right approach would have been to copy the disk bit for bit with dd http://www.cyberciti.biz/tips/how-do...e-command.html and then use fsck (Linux partition)or chkdisk (fat etc) and test disk to fix the disk and recover any partitions.