The August 2006 issue of Wired Magazine gives this handy tip for permanently removing deleted files from your PC so that they can not be recovered by another person with file-recovery software.
You do know that file-recovery software can resurrect everything you just emptied out of your Trash or Recycle Bin, right? It may look as if you’ve removed them from the hard drive, but the 1s and 0s of the so-called deleted files still exist. The only sure way to permanently erase sensitive material is to overwrite the disk space with new data.
Go to www.heidi.ie/eraser/download.php and download the free Eraser app, which uses a process rigorous enough to meet Pentagon standards.
Overwriting is easier on a Mac. (What isn’t?) Choose “Secure Empty Trash” from the Finder menu and the skeletons in your hard drive are toast.