If you did a MOVE operation, first thing to do is, on the main PC, go into Recycle Bin and try to recover everything you moved off to the external drive. Hopefully the "move" actually simply did something like a Delete on the internal HDD, which means it is still safe in the Recycle Bin and can be undeleted.
If you can get all your files back that way, then deal with the external unit. If it has failed you twice, do not bother trying to recondition the drive or fix up its Partitions. Just get it replaced entirely under warranty before you have more trouble!
Not covered by warranty any more? Still, consider replacing the drive.
Sorry, did not realize you had done the obvious already. You'd be amazed how often threads leap to the complex solutions before trying the easier ones.
Have you looked at GetDataBack NTFS? It's a third-party utility you must pay for, but they do have an interesting free trial system. You can run their utility for free on your HDD and it will show you exactly what it can find and recover. If you think it will do all you need you pay and get your stuff. If not, you back out and your HDD is left untouched for some other technique. Recovery is by copying files found, so you need an empty HDD with space for the copies.