Computer Viruses Explained

It happens at least once a week: a client, friend, or relative calls me in a panic and proceeds to explain, often in colorful terms, that their computer is acting strangely and they're afraid that they've caught a virus. I listen calmly, then make a trip to their home or business to diagnose the problem for myself. In my experience one, maybe two of these calls out of ten actually result in the discovery of a real virus. Admittedly that's only part of the story, so before you start thinking that viruses aren't a threat to your PC, let me explain.