The easiest and cheapest method uses an Ethernet connection, which requires a series of network cards, a cable for each computer, and a router. The network card is similar to the old modems we used in the past to connect to the Internet, however in a home network, it's used to communicate with every computer that's connected to it. In short, a computer virus is a software program designed to destroy or steal data. It attacks computers via distribution - often unknowingly - through email attachments, software downloads, and even some types of advanced web scripting. Viruses that destroy data are known as Trojan horses, viruses that explode their attacks are called bombs, and viruses that duplicate themselves are called worms. Many different programs often share Dynamic Link Libraries and you'll find a bunch of them in the Windows/System directory (but don't ever delete them)! .exe - This extension indicates a program or an application like Microsoft Word, Internet Explorer, or Outlook Express. Use extreme caution when downloading . 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. A project management program that you're interested in may require a specific operating system, like Windows XP for example. For example, when you're faced with an electronic system, look for a main menu. Most main menus display themselves as soon as a device is turned on, so chances are that if you're standing before a device that shows a bunch of choices to do something, you're looking at a main menu. The buttons on these main menus of course take you to additional menus, which in turn give you even more choices to make. 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.