I have a notebook with a Seagate Momentum 5400.6 in it. Suddenly it stopped working, only giving strange errors when trying to boot windows. I booted with an Ubuntu DVD, but Ubuntu couldn't fing the hard drive. So I tried putting it into an external case, and mount it through USB.
But same problem here: The hard drive is not mounted. I tried it on a MacBook, DiskUtility shows the disk (500.11GB ST950032...), three partitions (disk3s1, System Reserved and disk3s3), and that's it. The System Reserved takes a bit time to show up. When I try to mount one of the others, it says, that it couldn't be mounted.
The sound of the harddrive's spin sounds good, no clicking, beeping... Any ideas, how I can mount this harddrive?