It unfornate that you dropped the ext. HD. The problem as you noted, it's not recongized. That's a symbom of serious problems. So, I wouldn't hold out its going to work because you do some simple repair or s/w fix. If this was working when it happened all the more concerned that the problem isn't going away. If there any warranty, best to use it,. I wish it was better reply but it seems in that area of concern. I would take the HD apart(any warranty) if none then try to mount the HD into on a desktop system and see what the results are. I would also, try the s/w pgm. called,
pci file recovery.
It may help it may not, it alll depends on the damage. If you deem necessary then call on a data recovery service, it will cost.
I dropped my extrenal HD, a Fujitsu-Siemens Storagebird 640GB. it has inside a WD6400AAVS. i think everything is on it's position since i doesnt make any noise. It powers on but it doesnt get recognised. What can i do? Risk it opening it?