The concept behind computer viruses -- self-replicating software -- was first theorized by scientist John von Neumann in 1949 [source: Krebs]. Later, in 1983, a doctoral student named Fred Cohen coined the term "virus" to describe any self-replicating software that tries to modify computers. The name has stuck ever since.
Most viruses were originally created to strike against large computer systems, and so the average person didn't know about them until personal computers began to appear in regular households. At that time, hackers needed to physically distribute their viruses via floppy disks, which limited their ability to spread quickly. However, viruses became a real concern when modems became standard devices on most desktop computers. The most common ways for your computer to become infected with a virus are through e-mail attachments or corrupted Internet links.
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