Here’s an interesting little story that possibly gives a history on the advent of computer viruses.
IN January 1986, Basit and Amjad Alvi, sibling programmers living near the main train station in Lahore, Pakistan, wrote a piece of code to safeguard the latest version of their heart-monitoring software from piracy. They called it Brain, and it was basically a wheel-clamp for PCs. Computers that ran their program, plus this new bit of code, would stop working after a year, though they cheerfully provided three telephone numbers, against the day. If you were a legitimate user, and could prove it, they’d unlock you.
http://www.nytimes.com/2011/01/27/opinion/27Gibson.html