Most people have heard about computer viruses but don't understand them, which makes them more alarming.
Some people perpetrate hoaxes about viruses to prey on people's fears.
Your best defense is understanding how viruses work. A virus is a computer program that can reproduce and spread itself without you noticing it. Viruses are usually spread by people exchanging files. Virus-infected files can also be put up for downloading on the Internet. There are computer programs designed to detect and clean up viruses.