How to Really Erase a Hard Drive

If you delete a file from your computer, it does not permanently disappear. Just because a computer user deletes information from the hard drive does not mean it is gone from the hard disk. Using the delete command on a computer simply deletes the reference to the information, but the data is still there.

Difficulty: Challenging

Instructions

Things You'll Need:

• Floppy disk or a writeable CD

1. Make sure the computer was built after 2001. In computers built prior to 2001, the only way to ensure all data on the hard drive was erased is to physically harm the hard drive by physical destruction or degaussing. Most of these computers came with a DOS-level function called Secure Erase, but it is not turned on because the makers did not want people accidentally deleting everything from the computer's hard drive.

2. Download the Secure Erase program from the Internet.

3. Unzip the Secure Erase application and save or burn it to a writeable CD-ROM or a floppy disk.

4. Access the BIOS boot order to boot from the CD-ROM or floppy disk (whichever was used to save the application). Different computers have different key commands to enter the BIOS; generally it is the "F2" or "DEL" key. When the computer is starting up there is generally some text that tells what key to press to change the boot order (something like "Press F2 to enter start-up"). Press this key repeatedly as the computer is turning on. If the operating system screen comes up, the key was pressed too late.

5. Look for a setting option once in the BIOS that says boot order, boot sequence or something similar to that. Different machines have different BIOS layouts, but when you locate the boot screen, there will be options such as "Hard Drive," "CD-ROM" and "Removable Devices." Select the drive that contains the Secure Erase software (either the CD-ROM or floppy disk in removable devices) and move it to the top of the list sequence by the stated means that is listed in the BIOS. Again the keys for changing the order are different in some computers.

6. Exit the BIOS and let the computer finish turning on. The DOS prompt should appear. At the system/DOS prompt type in "hdderase" to start the process. The Secure Erase menu should appear and two options will be available: Secure Erase or Enhanced Secure Erase. Not all systems support the enhanced version and if not, this option will not appear. After selecting the command, it can take anywhere from 30 to 180 minutes to complete the operation. Do not interrupt the process because the system can lock up.

Tips & Warnings

• Be absolutely sure you want the information erased from the hard drive because it cannot be retrieved.

[shrek21]

on 6/27/2008 Nice post. If you delete data just by shift-delete that doesn't assure your data is completely removed or formatting hard drive doesn't delete data permanently. To permanently deletion of data you should use file eraser or drive wipe utility.

http://www.drive-wipe.com

Thanks

[timkirbylad]

on 11/10/2007 I am donating my old desktop. I have just restored the computer to factory settings, using the original recovery CD. Is all my personal data now irretrievable?

[vbiggar]

on 10/29/2007 Sorry, one more comment. In the past I have accidentally erased the wrong drive. Many times we buy one or more of the same type drive. When we go to erase a drive we can select the wrong drive by mistake. I recommend disconnecting the drive data cable for any drives you don't want to erase.

[vbiggar]

on 10/29/2007 I posted a article on this subject on my blog
http://thinkbiggar.blogspot.com/2007/10/spring-cleaning-on-that-hard-drive.html

It gives you some other options besides a complete wipe. On that site I have a link to:
http://dban.sourceforge.net/
Darik's Boot and Nuke

This app will wipe a drive also.
(what do you think of this application?)

Also good info in the 2001 drives, I never knew that. Can you explain this a bit more. If I do a surface scrub of a drive how can anyone retrieve the data with a older drive?