MOst hard drive failures are due to heat. The head's spinning constantly can often cause faiure. Often, if you have a drive "ticking" as said above, slap it in a sandwhich bag, in the freezer for a good time, put it in the pc and 9 times out of 10 if will be readable for small portion of time. Could be 5 mins, maybe 10. Generally enough time to get the data off and onto another drive.