scr - This extension indicates a screen saver file. .sit - This extension indicates a Macintosh archive StuffIt file. They will not open on a Windows system without a special utility. .ttf - This extension indicates a font especially designed for use on a Windows system. It stands for "True Type Font. Be aware however, that because shareware is not commercial software, you may not experience a full program the way you would if you bought the software out of a box. Shareware may or may not be limited - meaning that some functions may not be available to you until the program is paid for. These limitations are often small and don't interfere with the way its full version operations. A computer user only needs to touch various boxes on a screen to control a computer. Sure, the programming behind such technology is extensive and advanced, but to the end user, it makes computer use less intimidating and plain easy. Of course when we talk about operating a computer, we envision more involvement than speaking on the phone or touching things on a screen. User interface - this is the visual design of a program. It may contain squares, boxes, words, icons, and buttons. If you're experiencing insufficient memory for example, you might see black rectangles across the user interface of your software programs. Title bar - this is the top-most part of a program that displays its own name or it may describe the contents displayed in another part of the interface. There are a number of places available including computer store outlets, online stores, auction sites, used computer stores, or your friendly neighborhood yard sale. For the computer novice, we recommend buying a computer from a physical store. In a physical store, you have the opportunity to see the computer of interest in person and ask questions. 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.