Hard drive not detected after dropping but running

Hi,

It is a Western Digital 320GB External HDD. I dropped it accidentally after that it's not showing in explorer. It is running coz i cud hear the buzz of the drive. The drive was not connected when it fell. It had a drive manager pre-installed and i had password protected the same. So there was a pop-up asking for password every time it was plugged in. That is not appearing now When we are connecting it to another PC. It just shows WD External Drive Installed and ready to use. But nothing showing in My Computer.

Any help is appreciated.

Thanks