" Click "OK" and you'll notice that the files in Windows Explorer show a dot and group of three letters after their names. That dot and group of three letters is known as an "extension," and the extension explains what kind of file it is. A file could be a plain text file, an image, a sound, a video, or program. " "Scan Your Disk for Errors!" Although these two activities are important, there's more you can do to extend the life of your computer beyond today's predicted two-year span. In fact, by following the simple advice below, you can enjoy the use of your computer to up to five years or more - reserving expenses to simple software upgrades rather then complete and costly hardware upgrades. For just as this new lifestyle was once predicted, we're going to predict that "the old ways" will slowly disappear. We're going to predict that all paper-based transactions (checks, money orders, etc.) and documentation (think of the old filing cabinet system) will disappear. We're going to predict that chips will replace everything that was once transported from one location to another through the trusty post office. If the program were working with a simple algebra equation like, "x + 5 = y," the variables "x" and "y" would be unknown pieces of data. Or if a program were to calculate a date "x" days from now, the variable "x" would be an unknown piece of data until we tell the program what "x" is. "1 In the past, we would be comfortable in telling new computer users not to worry about viruses and that catching a computer virus is rare. Today, that would be some of the worst advice we could give anyone. As reported in countless news reports, computer viruses are rampant and they're extremely worrisome. But our job is unnecessarily made harder when people don't take the time to learn about computer accessories and familiarize themselves with the limitations of store-bought computers. Hopefully by the time you finish reading this article, you'll understand the lesson that we were trying to teach our client: "What comes out of the box is really just a starter kit.