I've been working with computers since 1977, and I had my own sideline business fixing computers for over 15 years. As a CompTia A+ certified technician, I can say that SpinRite is the absolute best hard drive diagnostic tool available. I've used it for many years, and it has brought previously deceased hard drives back to life. I am a Retro Tech - I love old computer stuff (just ask Yurei, he helped me toss literally tons of stuff out when I moved to Colorado). I have quite a few old drives, and SpinRite can go through to mark bad sectors even before the drive itself knows the sector is bad. SpinRite can do a media scan that does not harm the data already on the drive, and it writes a series of information to each sector, designed to artificially force the drive to have as many magnetic flux reversals as possible. This write/read process can find weak sectors and mark them as bad before they become data 'black holes'. As I am writing this, I am scanning a box of laptop hard drives that was given to me, and so far three of seven have been brought back from the land of the dead.