Despite his motivation or intention, his efforts were null. We wouldn't be surprised to learn if other motivations behind spreading viruses were similar to this person's, but that doesn't justify the damage that viruses do. Innocent people become pawns for the evil plans of others who've convinced themselves they're doing the "right" thing. The following list defines some of the most common extensions that you'll find on your computer. .au - This extension indicates a sound file. Most sound players will load up and play this kind of file. .art - This extension indicates an image file that was compressed with AOL (America Online) technology. One of the easiest and least expensive things you can do to extend the life of your computer is to get rid of unnecessary programs, folders, and files. A disk drive that's clogged with unnecessary and unused files is disk drive that works harder than it has to. Although Window's defrag system can ease some of the stress that these files place onto the drive, it doesn't do much to get rid of the problem in the first place. Most cash registers are Windows XP or Vista machines that send purchase details back to headquarters via the Internet (or a small Intranet). Having your weight, blood pressure, and heart rate measured and recorded is now a digitized process. Even ordering a pizza is now a simple matter of dialing from a wireless cell phone and making a few selections from series of pre-programmed menus! Program B uses a file that Program A installed much earlier, but when Program B is run, errors popup. Those errors are the result of Program B attempting to use an outdated (shared) file that was installed by Program A. In order to fix that problem, the user would have to download an updated version of the shared file (which to say the least - is not an easy thing to find or do). New computer buyers also have access to store warranties, returns, trades, and services. These suggestions should give the computer newbie a great start in selecting a quality computer for the first time and they apply to either Windows computers or Apple Macintosh computers. After making these decisions and finally selecting one that fits your needs, you can then venture into the fascinating world of software - a world that is just as grand as the world of hardware!