It All Boils Down to the Code
A computer virus is simply a set of computer instructions or computer code that is written by some unscrupulous person. This code is attached to some part of the normal computer operating system or computer program. Instructions in this code tell the computer to perform some task. This task is often a destructive one, such as deleting important information or crashing the hard disk. However, there are other benign viruses that may be only a slight aggravation. Some viruses have been known to do nothing more than put a large happy face on your computer screen.

How Does a Computer Get a Virus?
Just as a human virus is passed from person to person, a computer virus is passed from computer to computer. A virus can be attached to any file that you copy to your computer. If you download files from the Internet or copy programs or files from friends on floppy disks, you are very susceptible to viruses. Actually, anytime that you download files or put a floppy disk into your computer, you are susceptible to viruses.

Many viruses are spread through e-mail. Generally, you cannot get a virus from simply reading e-mail. Certain types of today's viruses, like Klez, are different. They are very dangerous because you do not even have to open an e-mail attachment to release the virus. Just opening the e-mail itself can release the dangerous bug.

Under normal circumstances, a virus becomes active when you execute a program that contains the virus. For instance, if you download a program from the Internet and it is infected with a virus, the virus will attack your computer when you activate the program. Viruses are everywhere. Although it is rare, viruses have even been found in commercial shrink-wrapped software.

How Do I Know If My PC Has a Virus?
The trigger that activates the virus can be almost anything. For instance, the virus can be activated the minute it is installed. On the other hand, it may initiate its dirty work the next time you start your computer. In many cases, a virus resides inside your computer in an inactive state, waiting for a certain event to happen. Like having a physical virus in your body, you can have a virus in your computer system and not even know it. A virus can wait patiently in your system and attack only on a certain date. Of course, in the time between the moment you contracted the virus and the time it made itself known to you, you may have innocently spread the virus to others.

Stop Viruses Before They Attack
A computer virus can do extensive damage. It can crash your hard disk. It can destroy all or some of your data. Many viruses do weird little things that adversely affect your computer. The most usual symptom of a computer virus is erratic behavior. The destruction can happen at any rate of speed and can affect almost any part of the computer. Viruses can spread quickly through today's intricate cyber world. If your computer starts to act a little weird, the first thing to do is to check for a virus.

If you are smart, you will stop viruses before they enter your computer. You can do this by purchasing a good virus protection program. Such a program will check all files for viruses. Once installed, an antivirus program can be set to work in the background. It will check all files before they enter your computer and will alert you if a virus is detected before it contaminates your system. If a virus is detected, your antivirus program will quarantine or eliminate it so that it cannot harm your computer.

Be very careful to purchase a virus protection program that matches your operating system. If you use a Mac, buy a virus protection program made especially for Macintosh computers. If you use Windows 98 or Me or XP, select a program that was written specifically for your operating system. Don't try to use a virus protection program that was written for Windows 95 on a Windows XP machine; this will really mess up your computer.

Keep Virus Protection Software Up-to-date
New viruses are written everyday. It seems that there are many people in the world who have a lot of time on their hands and a slightly warped idea of how to use their intelligence. Luckily, companies like McAfee, Symantec, and Panda Software are constantly scouting for new viruses and updating their antivirus software tools. They use any of a growing arsenal of weapons to detect and fight viruses.

In order to take advantage of these new antivirus shields, you must update your antivirus program on a regular basis. The company that manufactured your antivirus software will provide constant updates as they find new viruses. You should make arrangements to get these updates regularly to be sure that your computer is completely protected. Go to the Web site of your antivirus manufacturer to download new virus updates, or definitions as they are often called. Some newer antivirus programs automatically update your antivirus protection as well as the antivirus definitions when you log onto the Internet through a process called live update or online virus scan.

When you purchase a virus protection program, be sure to check out the company's update program. Some manufacturers give you free updates; others do not. If you already own a virus protection program but have never updated it, see the documentation that came with your program or contact the company that created your program to check on their update policy. If your program did not come with free updates or if you have already used up your free updates, you can purchase additional updates, usually for a nominal fee.

To keep you protected as much as possible, I recommend purchasing antivirus software that updates automatically. If you update your virus protection manually, a weekly update is mandatory; a daily update may be a good idea in today's virus-infested atmosphere.

Viruses and the people who write them are intriguing subjects. For more detailed information on the different types of viruses and how they work, visit the Symantec AntiVirus Research Center or check out the Virus Bulletin. Although the Virus Bulletin is a technical journal, it will give you good solid information and links to virus information and antivirus products.