In 1992, a computer virus was created called the Michelangelo Virus. It was released into the world to coincide with the painter's birthday in 1991, and set to erase all data on hard drives on March 6 every year thereafter. Over a period of time in early 1992, many computers and floppy disks were released and accidentally contained Michelangelo.
Mass hysteria broke out. Fear gripped the planet as many newswires predicted five million PCs would be affected. While all this was happening, however, virus experts predicted about 15,000. Nevertheless, the press stuck to their word. Since the press is a powerful force in peoples' minds, the people who owned PCs panicked.
The hysteria grew so large that antivirus software was stripped from shelves. When that ran out, users purchased virus-based books. Everybody was waiting for March 6, 1992 to come and go. It came and went. Reports indicated that between 10,000 and 20,000 computers were affected - a bit of a far cry from the five million estimated by the press. When disgruntled reporters rang experts to ask what the cock-up was, they replied "You just asked the wrong people."
By the very next day, newswires had stopped reporting about Michelangelo... and didn't print a single story about viruses until at least 2 weeks later. The virus continued to attack every year after that, but amounts of cases diminished a lot. By 1998, only two attacks were confirmed.
Source: http://www.vmyths.com/fas/fas_inc/inc1.cfm