I must admit, the idea of authoring such an article seemed daunting because the highly technical area of Internet security is, ummmm, highly technical. However, recent focus in the popular press has assisted in bringing attention to the vulnerabilities of Internet use and the need to protect our computers and the information they contain. This not only includes prevention of external intrusion, but internal intrusion as well. We have all heard horror stories about computer viruses, Trojan Horses, Worms and the like each with a unique capability to destroy files, data and entire systems, yet more than half of all users fail to protect themselves at the most very basic level from being infected with any one of these intruders. Although there is no widely accepted definition of the term computer virus, a loose definition is an executable code, that when run by someone, infects or attaches itself to other executable code in a your computer in order to reproduce itself.
Some computer viruses are intentionally malicious.
There are other viruses which are problematic simply because they infect other code or cause unintentional damage not intended by the author when the virus finds itself in a very different environment from which it was intended. A non-destructive virus can suddenly turn destructive. These modify the file system so that they can run prior to other programs. Unlike file infectors, they do not attach themselves to programs. Word processing documents can serve as sources of transmission for viruses that take advantage of auto-execution macros in products such as Mircosoft Word by simply opening the infected document.