usually when you get the clicking noise, its basically means your heads are damaged or crashed, you can't fix it yourself because it requires a clean environment, opening your harddrive and exposing the platter to a spec of dust would render your harddrive useless. So yea the drive is pretty much dead, unless you can get someone to recover its data, my cousin had a WD external and i noticed that it uses only 1 plug

, my classic freeagent external uses 2 cables one says (power+data, and Power), im guessing its to prevent harddrive failure cuz i abused that hard drive so badly lol, i leave it on plugged into my computer for like 3 yrs straight now with the light on lol, sometimes i accidently drop it a few times, but never had any problems with it since i bought it the first day.