Wiping confidential data when you sell your PC

If you are selling or otherwise disposing of an old PC, have you removed all the critical/confidential data? Just dumping all the files in the Recycle bin/trash can and deleting them is no where near adequate. The cheapest data recovery program can get those files back. They can even get files off a freshly-formatted hard drive. So if you want to be absolutely certain that your old PC's new owner won't get your private information, you need to wipe the sensitive files by overwriting them with new 1s and 0s. Here's some tips on what to do, courtesy of PC World.