The question i want to ask is, "How do i figure out if the used hard drive i purchased online is good?"
I bought a used "Western Digital Caviar Green 1.5 TB SATA III - WD15EARX" on amazon.com warehouse for $75. I read from different websites on reviews on this specific hard drive, and in general have a poor failure rate (due to some shipping damage or other). I had WD hard drives for many years and not one has failed on me. But i don't know anymore since Thailand floods have damaged production. I don't want to find out in 9 months that my data disappeared. So is there anyway to diagnose, (sound characteristics, software, odd behaviors) to see that it is a good or bad hard drive?
In either case of new or used, there's no way to know when a drive may fail. Doesn't matter whos drive you buy they all have failures. Backup your data. Even if you get a new drive you still can suffer a failure. Backup your data. The only good thing with new drives is you have a warranty for 1, 3 or 5 years. Doesn't cover data though so you know what I will say next.
You can download a program like HDDTUNE and run a full surface scan on it, checking for bad sectors and other problems. If there are none, then your odds are no worse than anyone else's for having a failure. In case you missed price_th's post, back up your data.