How to "Wipe" Your Hard Drive Clean

Afraid of identity theft? One way criminals can learn all about you is by mining personal data off your old computer's hard drive.

Remember: Just because you delete something doesn't mean it's no longer there.

A few years ago, a pair of M.I.T. graduate students bought 158 used hard drives off the Internet just to see how many had not been properly erased. It turned out most of them still held compromising information, including active credit card numbers, pharmaceutical records and more. One disk actually contained evidence the previous owner was having an affair.

So how do you thoroughly wipe everything off your hard drive?

Reality Check

First thing's first. Don't get carried away. It's one thing to be worried about data being stolen, it's quite another to be paranoid.

Most people are good at heart, and experts generally agree that if you give your old PC - with files deleted - to someone you know (or a needy cause, which I recommend you do), chances are slim the new owner will be doing anything malicious with it.

That said, it's a fact that bad guys are out there and there's always an outside chance that your hard drive could fall into the wrong hands. With that in mind, I will list the various ways to clean your hard disk, or "wipe" it, starting from the most basic to the deepest, most thorough, methods of erasure. You can choose the method that suits your needs (or level of paranoia) best.

Basic

Windows XP offers a utility to do this. It's a multi-step procedure (too many to list here), but is fairly simple and straightforward. You will find the information here:

http://support.microsoft.com/kb/310312

The above procedure is a simple cleanup of the disk. The next level is to reformat your drive, which will do a better job of permanently getting rid of all files and information. Details on how to do that are here:

http://support.microsoft.com/kb/313348

Now, unless a user has special data-retrieval software, reformatting your drive should be enough. If you want your hard disk to be more thoroughly cleaned, however, there are programs you can download that will do a more complete "wipe."

Freeware

There are many free products out there, but the one that seems to garner the most respect among techies is Darik's Boot and Nuke:

http://dban.sourceforge.net/

You download this product to your computer, then save it to a floppy or CD, depending on which one your computer accesses when it boots up. The next time you boot your machine, it will automatically delete the contents of any hard drive it can detect.

The makers market it as "an appropriate utility for bulk or emergency data destruction." As with all such products, be VERY careful how you use it, and read the instructions thoroughly.

Most important: Be sure and back up any files you want to keep.

Here are two other free disk-wiping products experts have recommended:

Active@KillDisk: http://www.killdisk.com/downloadfree.htm
Eraser: http://www.heidi.ie/eraser/download.php

Warning: Using such products may be harmful to your hard drive. If you wipe them repeatedly you may see a degradation in performance.

Commercial Products

If the idea of open-source products doesn't make you feel secure, there's always the option of buying something off the shelf. Here are two products:

WipeDrive by White Canyon Software for US$39.95: http://www.wipedrive.com

Active@KillDisk ERASER for US$29.95: http://www.active-eraser.com/

Both comply with U.S. Department of Defense standards for cleaning and sanitizing hard drives.

Destroy It

This may have put you off donating your old hard drive, and if so, I can understand that. But don't let it.

There are many people and organizations (like schools in poor neighborhoods) that desperately need used computers and would put them to good use.

However, if you're in a hurry, don't have time to do any disk-wiping (these products can take hours to do the job properly, by the way) there is an easy way to render your hard drive virtually useless: bash it to bits.

Wear protective eyewear and gloves, get the biggest hammer you can find and beat on it. If you have a sturdy power drill, then drill several holes into it too, making sure you go all the way through.

Theoretically, your data can still be retrieved, but you would need some extremely sophisticated software and hardware, and a large budget to do so, experts say.

Sources:

Lincoln Spector, "Wipe Your Drive Clean of All Its Sensitive Data," PC World. URL: (http://www.pcworld.com/article/id,110338-page,1/article.html)
John Woram, "DIY: Wipe Your Hard Drive Clean," CNET. URL: (http://www.cnet.com.au/software/operatingsystems/0,239029541,240053924,00.htm)
Leo Notenboom, "How should I erase my hard drive before I give it away?," Ask-Leo.com. URL: (http://ask-leo.com/how_should_i_erase_my_hard_drive_before_i_give_it_away.html)