What is a virus?
A virus is a program that loads itself onto your computer and executes instructions that can damage your files and even delete them. Viruses can use up your computer's memory, can prevent it from booting, and will spread to other computers via diskette. Nasty cousins of viruses are worms and Trojans. Worms are viruses that spread over networks and the Internet, often by hiding within e-mail attachments or already infected network directories. They can quickly replicate by exploiting commonly used programs such as email address books. Trojans infect your computer by hiding inside otherwise innocuous programs such as games, or they can arrive via email. While they don't replicate as worms and viruses do, they can be just as destructive as viruses.
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