The Simple File Shredder may be free but it sounds like it is not very secure. In order to completely eliminate a file (short of destroying your disc) the data areas have to be overwritten with random characters multiple times. I belive the DOD standard is seven seperate passes. There are some packages that will do that, but I don't know any free ones. And depending on the speed of your computer and how much data you want to delete, it can take quite a while to do a thourough job.