I am using an external western digital. I plug it into the PC and I hear it spinning but I can't see it in My Computer. Disk Manager reports it is OK, but it doesn't assign a name nor a letter. I cannot assign a letter by hand because all options when I right click are greyed out apart form Delete volume which I obviously DON'T want to do.
Also there should be two partitions but there is only one detected (of 930GB in size). Also Hard Disk Sentinel reports the disk is perfect.
The data on the disk should be recovered at any cost, but If possible I wouldn't give the disk to a data recovery company.