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Backup your system before doing anything Use DBAN. Make sure your computer is set to boot from a CD. Type “dodshort”. Hit enter.
. You should always backup important files before wiping (or erasing) your hard drive. Erasing your hard drive will make recovering your files challenging and you do not want to lose anything important. If your computer contained any sensitive documents, photos or information which could be used to steal your identity, you will want to use a more secure method of removing your data. DBAN (or Darik’s Boot and Nuke) is a commonly used, free program used to securely erase your hard drive. It also works for Macs running at least OS X. If it is not, follow these instructions. When the computer boots from the disk, the easiest method to wipe the computer will be to type in either “dodshort” for a simple wipe or “dod” for something stronger (leave off the quotation marks for both). Both are the standard erasing methods for the Department of Defense and are very secure. You can use the interactive mode if you want more wiping options. Once you’ve entered your preferred method, hit enter. You’re done: it will start wiping. You will, however, need to reinstall an operating system and restore your files.  It will take a VERY long time. Don’t worry. It’s normal.