Here are some examples. Banking is self-serviced through the desktop-clad ATM machine. Gas stations are self-serviced through a menu-clad touch screen kiosk. 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. But you can prevent identity theft from occurring by installing a firewall. A firewall is software that checks all data entering and exiting a computer and it then blocks that which doesn't meet specified security criteria (user-defined rules).1 5. Don't click on website links in spam messages. In an effort to obtain personal information, some spammers will send email that asks you to click on a link. This article will describe what viruses are and then point you in the direction of some rather unique protection and prevention. 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. With an operating system installed onto a computer's hard drive, users no longer need to boot a computer with a floppy disk, nor do they need to run programs from a floppy disk. All the drivers of a program are stored onto the computer and used whenever a program is started. Apple's Macintosh computer was among the first of a couple systems to establish a user-to-hardware relationship through a user-friendly interface. It's costly to produce and as you can probably guess, that cost is passed on to the end user: the consumer. Open source software on the other hand is free. Free to download, free to install, free to use, free to modify, and free to share. Started over twenty years ago, it's a phenomenon that is gaining in both popularity and exposure. 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." .txt - This extension indicates a plain text file that can be opened with Notepad.