When you think trash, you surely don’t think about your old, trusty personal computer. But that’s exactly what will become of it when you make the inevitable move toward your next laptop or desktop. And, yes, buying a new computer is inevitable, considering the pace at which computer technology zips along. Just think—about a handful of years ago, a fast microprocessor for a laptop was at 233 MHz. Now you’re looking at about at least 2 GHz! That’s Giga, with a G.

So eventually, you will want a computer that can handle the latest software, the latest games, and the latest interactive Web sites, and then you’ll have to throw away your old computer, right? Wrong. Try selling your used computer instead. Throwing out your computer is one of the worst things you can do. For one, your computer may be useful for someone out there, even if just for scraps.

Trashed computers and other digital equipment also make up one of the fastest growing, and most dangerous, new trash “categories” out there in your neighborhood landfall. On one hand, computers are generally bulky and made of plastic and other materials that won’t be breaking down in a landfill for the next few million years. What’s more, other materials in your old computer are highly toxic to the environment, like mercury, lead and cadmium. They’re so toxic that their actually name in the waste-management field is “toxics.”

You don’t have to be a techie or a scientist to understand the danger in that—nor the benefits of selling your computer. On the Internet, there are a vast number of auction and classifieds sites, some better than others, where you can “download” you computer to a worthy buyer.

Before you boot up your replacement laptop or high-performance PC, however, be sure you read and compute the following tips. These tips will help you avoid the crashes and shutdowns that befall the computer seller who doesn’t do his homework first.

Hold onto all of the operating system and software manuals that came with your old computer. This will add value to your sale, not to mention it will make you a trusted seller for offering up these helpful books to the buyer.

Erase all personal information from the hard drive. And we’re not just talking about simply putting stuff in the “trash bin.” It’s extremely important to purge all data from your computer’s memory repository, even from invisible backup files on the hard drive. If you’re not sure how to do this, ask your IT expert at work or a techie friend for advice. You don’t want the next user to have access to your bank accounts, old e-mails, and other private info, do you?

Uninstall any application from the hard drive that you’d like to use on your next computer, keeping the installation disk and the software serial number for yourself. When it comes to software, the manufacturers made sure that you never really own software, you license it. So you don’t get free reign to keep software on multiple computers. You only get one license, so you need to bring your licensed version with you to your new computer.

Do your homework on your computer’s worth. Just like you would for a car, check around at other classifieds and auction sites to see what other people are selling your make and model for.

Be sure you want to truly get rid of old faithful. You may be able to repair your old laptop rather than buy a new $2,000 Centrino model. Or you may be able to add RAM memory and a new hard drive to your four-year-old desktop rather than invest in a new $3,000 multimedia masterpiece. In other words, do a thorough cost-analysis of what it would take to rebuild your old computer, versus what it would cost to sell it and buy a new one. And check your heart too. You might be surprised just how attached you are to your old faithful.

Once you go through these steps, you are prepared to make your move and sell, sell, sell. And then, of course, you’ll be ready to start on a whole new list of steps—for buying a new computer. But that’s a topic for another article!