You're sick. You've got a fever, the chills, and a headache so horrible that you can't think straight. No matter who claims to desperately need your help, you are not going to get out of bed. Your computer can suffer the very same thing--a virus. And, in the worst-case scenario, it might cause your computer to refuse to start up.



The term "virus" in the computer world comes from exactly where you might think--the term used for illnesses like the common cold. Like a biological virus, a computer virus spreads by making and sending copies of itself to other computers.

A computer virus causes a lot of trouble in a computer and the infection occurs without the consent of the user. The copies it makes of itself could be exactly like the original virus, or they might vary a bit. They typically spread over a network or via the Internet.

Many people lump all malicious programming under the label "virus." However, a virus is something completely different from a worm or a Trojan horse. Unlike a virus, a worm can't spread on its own; it requires some action from the user, such as opening or running an infected file. A Trojan horse is a file that tricks the user into running it by appearing to be harmless.

Viruses cause problems for computer users by harming programs, reformatting the hard disk, or deleting files. Although the vast majority of viruses are created for the purpose of doing harm, there are a few that are meant to be harmless pranks that merely display video, audio, or text messages. Regardless, these viruses still use up memory without permission.

The fist virus was dubbed "Elk Cloner" and it was made to run on the Apple DOS 3.3 operating system. It was created by a high school student named by Richard Skrenta in 1982. It was a joke virus that was transmitted using a floppy disk containing a game.

The disk could successfully open the game 49 times; on the 50th the virus was activated. It caused the screen to go blank and then display a poem reading: "It will get on all your disks. It will infiltrate your chips. Yes it's Cloner! It will stick to you like glue. It will modify RAM, too. Send in the Cloner!"

Brain was the first virus for the PC. It was designed in 1986 by brothers Basit and Amjad Farooq Alvi. Their purpose for creating the virus was to protect legitimate software they'd written from being copied illegally.

In the early days of viruses, the usual means of infection was through some form of media that could be moved from computer to computer, like a floppy disk. However, today, it's easier for viruses to be spread over the Internet or through computer networks, so most are designed to do just that.

Because of the popularity of the Windows platform, the majority of viruses are designed to exploit weaknesses in the Windows operating system. However, that's not to say that there are no viruses affecting other operating systems. The truth is, no matter what operating system you're running, unless you take steps to prevent virus infections, your computer is vulnerable.

There is an entire industry of virus protection software. The most common ways these anti-virus programs work are: 1) Detecting viruses using signature definitions, and 2) Detecting viruses using a heuristic algorithm that recognizes typical virus behaviors.

A program that uses signature definitions relies on the user to keep the list of definitions up to date using updates and patches put out by the maker of the software. These are usually available at no cost with purchase of the software or through a paid subscription to the software.

The algorithm method is able to find viruses for which no signature exists.

Other ways of protecting your computer against viruses include making backups of your data and operating system on media not stored on the computer's hard drive. This way, if your computer should be infected causing a loss of data or the inability to start up the computer, you can restore the computer.

If your computer becomes infected, it's unwise to continue using it until the virus has been removed by completely reinstalling the operating system. This is a time-consuming process and often results in lost data. So, as with a virus in the human body, "an ounce of prevention is worth a pound of cure." An anti-virus protection program is absolutely essential to the health of your computer.