We often joke around the office about the "grandma" who refuses to use a computer until she can afford the "latest" one. Chances are, Grandma isn't ever going to shell out the bucks to buy the latest computer on the market, nor is she going to know how to use it once she gets it. What Grandma doesn't realize however is that a used computer is an excellent training tool that she can use to prepare herself for something "better" in the future. " Button - buttons perform a command after a user clicks them with a mouse. Problems occur when the text of a button is grayed out or if it doesn't appear to sink into the screen when clicked. Check box - a check box is a small box that allows a user to indicate several choices among many. When clicked, a small "x" displays inside a box. For the novice, it's best to buy a computer that has all of these components included so that when it's taken home, assembling the computer is a simple matter of plugging things in where they belong. Save the individual purchases of these components for those who have more experience. 2. Decide what you'll use the computer for. A prime example of this kind of error is when users attempt to use software that isn't applicable for their system. Almost all software accompanies a list of system requirements which dictates what a computer needs to have in order for the software to work properly. To minimize errors of this sort, always verify that your computer has the required components. Customizing your PC is what makes using a computer truly unique and enjoyable, so have fun and build a situation at home or a work in which you'll love to work with everyday. Should you feel a little nervous about it at first, remember that your computer's original configuration can be saved to a back up file should you ever want to restore it to the same state that it was in when you first bought it. Okay - we're assuming that the reasoning behind hiding extensions is a "user-friendly" one because we just can't come up with any other reason for hiding them. No harm could ever come from seeing an extension, but plenty could be learned from it. Fortunately you have this article to guide you through some of the most common extensions that you'll run into.