Courtesy of Florence Klein, Founder, SilverPlanet.com

Are you thinking about putting Ol' Nellie out to “e-pasture”?

In other words, are you thinking about getting rid of an old computer?

No problem, but you need to make sure the bad guys can't access private information left on the hard drive—personal and financial information, passwords, account numbers, license keys/registration numbers for software programs, addresses and phone numbers, medical and prescription information, tax returns, and so on. Let's start with basics.

Understanding hard drives

A computer hard drive stores data and maintains a file index. When you save a file, especially a large one, it's scattered about the drive in pieces. Files are also automatically created by browsers and operating systems. When you open a file, the hard drive checks the index, gathers the pieces, and reconstructs them.

When you delete a file, the links between the index and the file disappear, telling your system that the file is no longer needed and that the hard drive space can be overwritten. But the pieces of the deleted file stay on your computer until they’re overwritten, and they can be retrieved with a data recovery program. To remove data from your hard drive permanently, they must be wiped clean.

Cleaning hard drives

Before cleaning your hard drive, save critical files on an external storage device (e.g., external hard drives [Firewire drives], USB drives [jump or keychain drives], CD-ROMs), or transfer them to a new computer. Check your computer's manual, the manufacturer’s Web site, or its customer support line for information on how to transfer data to a new computer.

Utility programs to wipe your hard drive are widely available online and in stores. They’re generally inexpensive; in fact, some are available on the Internet for free.

Wipe utility programs have varying capabilities: some erase the entire disk, whereas others allow users to select files or folders to erase. Their effectiveness also varies. Programs that overwrite or wipe the hard drive many times are very effective; those that overwrite or wipe the drive only once may not prevent information from being recovered later. If your computer contains sensitive information that would be valuable to an identity thief, use a program that overwrites or wipes the hard drive many times—or remove the hard drive and physically destroy it.

If you use your home or personal computer for business purposes, check with your employer about how to manage business-related information. The law requires businesses to follow data security and disposal requirements for certain information related to customers.

Computer disposal options

Once your computer is "clean," you can donate it to a charity or other organization, resell it (perhaps through Craigslist or eBay), or recycle it.

• If you decide to recycle, remember that many computer manufacturers have programs to recycle computers and components. Check their Web sites or call their toll-free numbers for more information.
• The Environmental Protection Agency has information on electronic product recycling programs on its eCycling page.
• Your community may have a recycling program. Check with your municipal or county government, including the local landfill office, for regulations.