Hello all,
I purchased an HP Pavilion 7966 1.7GHz P4 in 2001 from Best Buy. It has an 80GB Seagate ST380020A drive in it that over time got very noisy (making whiny, screeching noises) and so I purchased Gibson Spinrite and ran it on the drive. Spinrite found tonnes of bad sectors, and each time I ran it (I ran it 2 or 3 times) it found even more. The drive continued to get even noisier and Spinrite said it was dangerously overheated. I don't have any extra hardware in the machine, so the airflow should be as good as it was when purchased. Well, I went into Best Buy and asked if my drive could be replaced under Seagate's three-year warranty. BB said that because I didn't purchase the drive OEM directly from Seagate, it was only covered by BB's $300 three-year warranty (which I didn't purchase). So I swallowed the loss and purchased a Western Digital Caviar 120GB drive from ZipZoomFly.
I have Norton Ghost and Ghostcast Server at work, so I took my machine to work with the purpose of imaging the 80GB and then putting the 120GB in and dumping the image back down. Well, suddenly the Pavilion no longer recognises the Seagate: it says 'hard drive not found' when I boot it up. Is that drive totally toast?
(And yes, I make regular backups every few months but still want to get what's on the drive.)

Well sorry to say but it's not looking good for you with that drive. I bought a Seagate 200gb drive today ($75 after rebate + 5 year warranty = good deal) and hope mine will turn out better than your experience. Unplug the IDE cable from the Seagate drive and then plug it right back in. Turn on the computer and see if that helps. Sometimes little things like that can do it. Also, I have a friend that one time had a dying hard drive and he stuck the drive in his refrigerator for about half an hour and let it get really cool...he was able to get his data off of it after that. I know it sounds crazy, but when you have nothing to lose, you may as well try it out.