Have you tried to look at it with fdisk ??
If the hdd was not running when it was dropped it should ?? be OK as the read/write heads are parked on what is called the CE cylinder,,and,, even if they hit the hdd ,,at that point,, no harm will come to the hdd,you may have to fdisk the whole drive though as a new bad track map might be needed,if you check the manuf's specs you will see that any given hdd is rated at XX gravities ...I dropped an 80g hdd on a cement floor last year ,I think,and it is still in use...:)