Viruses, Worms, Trojan Horses

The three main types of malicious software - viruses, worms and Trojan horses - are similar in many ways but act differently once they are in a computer. Your best defense against them is an up-to-date antivirus program. (See the glossary of terms for definitions.)

Make sure your definitions are being updated on a regular basis - at least once a week. Daily definition updates would be wiser. Go into the program you have and look for the date on the virus definitions. If it's more than a week old, they are not properly updated.

Don't confuse updated virus definitions with updates of the program itself. New versions of anti-virus programs are released regularly; often a new version is released each year. New definitions are released weekly or even more often. To receive virus definitions as they are released, you must have an active subscription.

Program versions often will continue to work even when they are several years old, but you lose the advantage of the new features being offered in the newer versions. Before renewing the subscription for your current antivirus program, consider the cost of buying a new version instead. You may find that for about the same cost as extending the subscription for the program you have that you can buy the newest version with a year's subscription for definition updates.

Eventually manufacturers stop supporting old versions of their programs, and no additional updates will be issued. The program then must be replaced with a new version.

The most common anti-virus programs for home users are Norton Antivirus from Symantec, and McAfee Antivirus. Both have the ability to update themselves easily, either by initiating an update from inside the program or by setting them so that they will automatically download updated definition files while you are connected to the Internet.

Comparing Security Programs

From time to time security programs come on the scene and show great promise and then fade. As a result, regular comparisons of the programs that are available help users decide which programs to use.

A good source is the web site of AV-Test.org which does program comparisons and has other information on computer security issues as well.

Computer magazines also can be a good source.