How to Permanently Erase Data Off a Hard Drive

Method 1 of 3: Boot and Nuke Method This will allow reuse of your hard drive, the theory that your data is still recoverable by forensic analysis by well-financed governments, is based on a misunderstanding of a research paper from the mid 90s by Peter Gutmann, which looked at MFM floppy disks, not modern EPRML hard drives. 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] 1 Download Darik's Boot and Nuke (DBAN) here. 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 BurnCDCC 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 far more than needed. Overwriting with "one pass of random data" is sufficient to prevent any recovery of data.