blackest Loc: Ireland

If it's spinning ddrescue is pretty good it takes a long time (might take a week) but it builds an image file of the drive so for a 2 TB drive you need s drive bigger than that for the image. Now once you have the image testdisk or photorec can work on the image and usually does a pretty good job of repairing the file system and recovering the data. Its better to work off an image than the physical disk since if sectors can't be physically read or written too then they can't be repaired on the physical disk.

If the drive isn't spinning it can be the heads stuck on the drive, you can open the drive wind back the heads close it up and there is a fair chance it will spin up for a while. It will not last long by opening up the drive you introduce dust which is like boulders to the drive heads. I did it and got 90% of the data back in the 2 hours a 1TB drive ran for.

If the drive is usb most externals plug a sata drive into a usb converter board plug the sata drive into a different controller it may be fine that board is a weak point. This may not work for some western digital drives as the usb is built in to the drive. Firewire and USB controllers are different I've found a good drive wouldn't work when swapping between a firewire and a usb enclosure. The drive was fine in its original enclosure though.

Obviously the best option is to not get into that situation in the first place and have a backup. All drives will fail.

ChuckMc Loc: Prescott, AZ

You might first put it in the freezer for 24 hrs. If it then works, be prepared to immediately copy the data.
Good Luck

This is a good time to encourage you all to BACKUP. A backup should have three copies. Two could be in our PC, the third should be external and ev en off location. Hey, I used to charge a lot of money for such advice. :-)