I bought a cheapo hard drive a few years back and had all my stuff on it, pics of my kids,family etc and it suddenly wouldnt work i somehow managed to get the pics off and its got the same clicking issue as you! i went and bought a 500gb lacie rugged hard drive and touch wood its been fine for about 3 years now ive not got it backed up though so im going to have to do that at one point! good luck with getting it sorted and hopefully it doesnt have too much valuable stuff on it