Boot and Nuke Method

This will allow reuse of your hard drive, but theoretically your data is still recoverable by forensic analysis by well-financed governments. Lifehacker describes the software that you will be using, Darik's Boot and Nuke, as "an open-source boot disk utility (read: works on nearly any computer) that supports a wide variety of disk wiping methods and operates from inside the computer's RAM, allowing it to scrub the disk thoroughly at a remove."

1) Download Darik's Boot and Nuke (DBAN) [ Register or Signin to view external links. ] . Two different versions (one for PCs and newer Macs, and the other for older Macs) allow DBAN to work on nearly every computer made within the last ten years.

2) Burn DBAN to a CD. Since DBAN is an ISO file, you will need to use burning software that can burn ISO files (also known as CD images). Simply burning the file onto a CD in the ordinary way is not sufficient. If you don't see the "ISOLINUX" folder on the burned CD, it won't work and your hard drive will not be erased.

Windows 7 comes with the correct software to burn ISO files; simply double-click the file. If you are using an older version of Windows, download a program such as [ Register or Signin to view external links. ] if you don't have suitable CD burning software.

3) Boot from the CD. Leave the CD in while you restart the computer you are erasing the hard drive with. If it doesn't boot up from the CD automatically, you will need to adjust the boot order in the BIOS. On an Apple Mac, you may need to hold down the "C" key while the computer starts up.

4) Delete the data. You will need to select the disk to delete the data from (make sure it is the right one because you can't recover the data after it has been destroyed). You can choose how many times you want it to be overwritten and deleted. The default, 3-pass overwrite is acceptable. Generally overwriting with "one pass of random data" is sufficient to prevent casual recovery of data.




Physical Destruction Method

This destroys the hard drive, rendering it completely unusable (and therefore unreadable). You can also view more tips in How to Destroy a Hard Drive. Physical destruction is a good option for an archaic drive for which you don't have the necessary interface on a computer to connect it to, or if the drive will not reliably boot for you to run a software-based erase. It is also for those who want their data to be unrecoverable even under forensic analysis by governments.

1) Remove the old hard drive you want to destroy from the computer or external enclosure (such as the outer case around a USB hard drive).

2) Unscrew all the screws holding the top on. You will need the T-9 sized wrench for most hard drives. Sometimes there's an air seal. You will need to remove this.

3) Destroy the platters. Once you get the top off you will see two or three stacked, silver disks (called platters). Put scratches on the surface of the platters with the Torx wrench. Now start smashing it with the hammer. Do this outside on a hard surface (such as concrete). Be sure to wear safety glasses to protect against flying debris. Glass platters (found on newer drives) will shatter. If you have a large hammer (a 10 lb sledge for instance): you can forgo opening the drive - a few good hits with a big hammer can split open the metal casing and mangle the platters, even on old full height 5.25" drives with metal (rather than glass) platters.




Selective File Wipe Methods

1)

• [ Register or Signin to view external links. ] : Secure delete files, directories or sanitize free space
  
• Wipe File: Overwrites the specific disk space occupied by the file you'd like erased.
  
• DeleteOnClick: Has a "Securely Delete" option to engage a Department of Defense 5220.22-M overwrite on the files.
  
• Eraser: Can be scheduled to perform regular overwrites of empty disc space to catch orphan files
  

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