Some states even prohibit the dumping of computers and related items such as monitors, printers and hard drives, so learn the law in your area.
If your computer is less than five years old, it's probably a candidate for re-use by another individual or organization. But don't just assume that it is -- many recipients have limited or no capability of repairing hardware and you don't want to burden them.
The EPA suggests making sure you have a functioning system that comes with a working monitor, wiring and software licenses. You should also check with the organization you're donating to -- it might require that donated computers meet basic standards such as being equipped with Windows 95 or having a Pentium processor. (Some organizations will even charge a fee to accept older equipment, so it pays to know.)
If you can't donate your computer, consider recycling it. You'll help the environment by reducing electronic waste. There are many organizations that recycle electronics. To find one, check with your state or local government's Web site. The EPA Web site also lists various agencies that will accept computers for reuse or recycling. Visit the site.
Before you donate your computer, be sure to purge it of all important records or you leave yourself open to risks such as identity theft. Simply deleting your files or reformatting the hard drive isn't enough. You have to purge your hard drive completely. Several programs can help you wipe your hard drive; a free one that works well is Eraser 5.7, available at CNET.com. Check out the site.
Marshall Loeb, former editor of Fortune, Money, and The Columbia Journalism Review, writes "Your Dollars" exclusively for MarketWatch.
To snag a tax deduction, make sure the organization you donate to is registered as a 501(c)(3) with the IRS, and collect a receipt. UsedComputer.com suggests getting an instant online appraisal from the Orion Blue Book for $3.99. Visit the site.