I mention an anti-virus approach in my books, but apparently the topic is confusing to some people. Let me elucidate.

There are two ways to run most anti-virus programs, active and interactive.

Active. In the active mode, the anti-virus program is on all the time. It’s constantly monitoring your computer system. If you download a file from the Internet, the file is scanned. When you get an e-mail attachment, it’s scanned. That happens automatically because the anti-virus utility is constantly monitoring your computer for signs of infection.

Interactive. The interactive mode is how most computer software works. For anti-virus software, that means that it works only when you run the program. Otherwise, the program doesn’t run.

In my books, I recommend that you use two anti-virus programs. Select one of the big-name programs, like Norton or McAfee, as your active anti-virus program. Set it to constantly monitor your system, which I believe is the default for both programs (meaning that there is nothing more to do).

Don’t forget to maintain and update the virus signature files! That means you’ll have to pay for the subscriptions. The price is worth it when computer security is important to you.

As your second anti-virus program, choose one of the lesser known anti-virus utilities, such as Kaspersky or AVG. Do not run that program actively; set it so that it won’t automatically monitor your computer. After all, you don’t need that kind of protection when your first, active, anti-virus program is doing that job.

Every so often, and for extra protection, I recommend that you use the second anti-virus program to perform a full system scan for signs of infection. So while the first program is constantly monitoring the computer, the second occasionally steps in and picks up something that the first program may have missed.

Yes, this type of redundancy seems like a waste of time. But consider that the bad guys know about Norton and McAfee. They know how those programs work and they know how to sneak around them. The bad guys know less (and could care less) about other anti-virus utilities. So there is a chance that your interactive, second-choice anti-virus program may catch something that the big guys won’t. That’s the whole point behind my recommendation of using two anti-virus programs.