I teach computer courses throughout the country. To encourage class participation, when students ask questions I give them a piece of candy. Eventually the question of computer viruses comes up.
Students usually say yes and then laugh.
Loading software on to your computer is analogous to eating candy. Viruses are transmitted when you insert a diskette into your computer, copy the software on to your hard drive and run it. A virus may also infect your system by downloading software off the Internet. For example, you get an e-mail message with a program attached to it. The message warns you about a virus and tricks you by stating the attached program is the antidote to the virus.