Anti-virus Protection.

• Position: Brief Article

When it comes to computer viruses, no one is immune, says Mickey Applebaum, a virus hunter at the Salt Lake City-based network systems service Connect II. Computer viruses are like biological viruses in the sense that the smarter and stronger our weapons for fighting them, the smarter and stronger they become.

Viruses began with the classic, and surprisingly simple, Michelangelo virus, named because it was distributed on Michelangelo's birth date. Larger "worm" viruses, like Melissa, spread when program software, such as e-mail, is opened. The Melissa virus infects everything connected to the computer, and potentially the user's Internet service provider (ISP).

The largest viruses, called payloads, are self-distributing, like SIRCAM. A. Another, called CodeRed, can attach itself to DSL routers and shut down every PC on a...