Eventually, every computer reaches the end of its useful life. If you are recycling or reselling your old computer or even kicking it to the curb, there are a few steps you should take to ensure that any future owner can't get more out of it than you bargained for.

Your personal computer likely contains a lot of information that would be a gold mine for identity thieves — account numbers, addresses, passwords, tax returns, credit card statements. To prevent this information from falling into the wrong hands, you should take care of this information before you dispose of the computer.

Sensitive personal information resides on the hard drive inside your computer. The hard drive is like a chalkboard with no eraser. When a program wants to record some data on the chalkboard, it hastily wipes a spot clean with its hand and records the data there. After a while, the chalkboard is covered with half-erased messages. In the same way you can read the remnants of half-erased messages on a chalkboard, an identity thief can read your information from the erased files on your computer. Consequently, deleting files from the hard drive is not enough.

Back it up

The first order of business in disposing of your old computer is to back up the files that you want to keep. Copy any files you will want in the future to a CD ROM, USB drive, external hard drive, or a new computer. Check your owner's manual, the manufacturer's website, or its customer support line for information on how to save data and transfer it to a new computer.

Wipe out the data

Utility programs to permanently delete the files on your old hard drive are available online for little or no cost. Additionally, commercial security products often provide file wiping capability as well.

Some utilities will erase the entire hard drive, others will erase selected files. They also differ in how thoroughly they erase the data: some overwrite the hard drive with random data multiple times, others just once. Consider using a utility that erases and overwrites the data multiple times.

Alternatively, you can remove the hard drive from your computer and physically destroy it. In fact, this is probably the most effective method of wiping out the data. If you have a hard drive that has "crashed" and is no longer functional, consider giving it a few smacks with a hammer for good measure. Just because you can't get it to work doesn't mean someone else won't.

Recycle, Donate, or Resell

Finally, there are a number of ways of disposing of your old computer once your personal information has been removed from it. Older computers may contain a certain amount of hazardous material, so it is best to keep them out of the trash stream. Many manufacturers (and some local communities) provide recycling facilities for computers past their prime. The Environmental Protection Agency (EPA) has information on electronic product recycling programs here.

Many local communities have organizations that collect old computers, refurbish them, and donate them to local charities. This option also may provide you with a tax deduction.

You might also consider selling your old computer online via eBay or Craigslist, or giving it away at www.freecycle.org. Once you have securely removed any sensitive personal information, you can part with it without worrying about identity theft.