Check the USB connections. If you took the case apart check the USB soldering to see if it looks like it's loose. I would also check for burn marks on the board or anything that doesn't look right. Can the drive be hooked up externally long enough for you to transfer the files over? (Do copy, not cut)
But if your data is encrypted then it might not work then. I don't know whether WD will try to help you recover your data but always back up important information. Hope your able to recover the data though!