[Technogeek]

Just as Kheldar said, I know this to be true. I have destroyed a HDD with a magnet, and not a hugh one. Yes it was on, and It was for a test in one of my computer classes. The teacher asked us this very same question, so we deiced to try it. We held the magnet to the HDD when the computer was off, and when it was on. When it was off, nothing occured, but when it was on, the hard drive became corrupt, and had errors all though it. It would not work, and could not be repaired. It did make some noise when we stuck that magent next to it.