That clicking is probably the read/write heads that were likely damaged in the drop, very likely if the drive was active when dropped. It's not something that you can repair and if you can still get the drive to work remove any important data and back it up right away.
the hard drive spindle head has hit the magnetic platter making a nice round scratch
the head is stuck in that scratch making noises
you cant repair the drive as the magnetic platters are being scratches, in time the scratch will develop into bad sectors (rust) and the drive head can't move out of the scratch
time to get a new drive my friend, and be more carefull next time