It may be perfectly fine, but the WD interface is broken.
I have a My Book that got knocked off a desk, with the result that the HDD could not be read. As I had nothing to loose I opened up the case, took out the drive and tested it in a port on my desktop, clearly the drive had had it. I got out another spare drive out of my NAS array, formatted it with NTFS, as is required with the WD interface and tried that out. No luck WD reported 0 bytes.
Further investigation led me to a program that sits on the HDD and acts as a driver interface. If this gets corrupted then your drive can be fine, but is reported as having 0 bytes of data.In my case I had neglected to install it.
This all depends on whether you use a desktop PC or are stuck with a laptop, as a drive bay is required. You can buy external drive bays, so that is an option.
Remove the HDD from the case and connect to a sata port on the PC or external bay. I built my PC, so it has an external HDD drive slot on the top.
Check the drive out with Disk Management, or any third party disk checking software. This makes it easier to recover your sensitive data yourself, or in fact do any number of non destructive operations yourself.