Banged drive over, pulled out USB cable in the process

"Have you tried running any disk/file recovery applications like Norton Utilities to see if they can access the drive?

I would start there, if they can't access the drive that doesn't sound good ;-{

You will likely need to send the disk into a disk recovery firm who will open the disk up and try to fix the heads as they likely have crashed. Remember your HD is like an old phonograph player so when you bang it you scratch the disk. In this case the vey small heads get ripped off and hopefully you didn't damage the platers. I must warn you this is a very expensive repair!"