A computer virus is a malicious program that attaches itself to another program or file with the intent of spreading or replicating itself.  Some viruses cause only mildly annoying effects while others can completely destroy your hardware, software, and files. Almost all viruses are spread by executable files attached to an e-mail. Unless you run or open the program, a virus cannot infect your computer. That is why you should NEVER open a strange-looking e-mail from an unknown source.

            Like viruses, worms spread from computer to computer; but unlike a virus, a worm has the ability to take advantage of your computer’s file or information transport feature to spread without human assistance. This is why worms are so dangerous. Left unchecked, a worm could send out thousands of copies of itself from your computer, creating a devastating ripple effect.  For example, many worms will access your e-mail address book and send a copy of itself to everyone you have listed. If it is able to install itself on the recipient’s machine, it performs the same broadcast to everyone in their e-mail address book, and so on down the line.

            Because of the copying process they initiate, worms use up system memory and network bandwidth causing Web servers, network servers, and individual computers to stop responding. In some cases, like the Blaster Worm disaster, a worm can actually allow malicious users to control your computer remotely.

            A Trojan Horse received its name because of the way it tricks users into installing it on their computer. To an unsuspecting user, a Trojan Horse will appear to be useful software or files from a legitimate source.  Once activated, the damage can be mildly annoying (like adding silly icons to your desktop) to outright devastating (deleting files and destroying information on your system).

            In addition to damaging files and destroying information, Trojans are known for creating an entry point that allows outsiders to access your system and possibly even steal confidential, financial, and personal information. Unlike viruses and worms, Trojans do not reproduce by infecting other files and do not self-replicate.

How To Protect Yourself From Getting Infected

            Since new threats are developed daily, it’s important to stay vigilant about keeping your computer or network’s security current. The most obvious line of defense is up-to-date virus protection that has the ability to scan and clean inbound and outbound e-mail messages. Next, make sure you have the latest security patches and updates installed for your operating system, especially if you are running Microsoft Windows. You should also have a software or hardware firewall installed.

Finally, modify your browsing habits. Do not click on pop up ads, download “cute” screen saver programs or emoticons, and never participate in peer-to-peer network download sites.