I have a hard drive that is giving me problems, but the problems are related to my use, and not problems with the hardware itself. I am considering selling the hard drive on ebay, or some other similar place. I'm just wondering what I should do to ensure that any data I once had on that drive is not recoverable. No it's not "kiddie porn", it's stuff like financial records, personal data files, etc. Are there any programs I should use, or will just formatting it, filling it up with large files, formatting again, and repeating do it?