Every once in a while we get a drive sent in that we are not able to recover. This drive came to us from a client who had let a relative take a look at the drive and try to recover it. It is hard to say how exactly the scratched platters occurred (it might have occurred the moment the drive failed, or it could have occurred while the relative attempted a recovery), but the result of the platter damage is that the data could not be recovered.
The pictures below show the drive, as well as the drive opened up. You can see where the surface of the platters are scratched. They should be like a mirror with no imperfections at all. You can think of this situation as having a DVD or CD that is badly scratched. The DVD or CD player will not be able to start reading the disk at all and will just eject it after a few seconds of trying.
If your drive stops working and is making any kind of weird sound, please stop using it and consult an honest data recovery technician. By turning off the drive and not powering it on until a recovery technician can open it in a cleanroom, you are maximizing the chance of a successful recovery by minimizing the chance of irreversible damage to the drive.