There is no direct figure as to how many computer viruses there are because new viruses emerge almost every day. However, in 2008, there were more than 1 million computer viruses. According to zdnet.com, in 2012, the Symantec virus definition file contained over 17 million separate signatures.
The first computer virus was detected in the early 1970s and was known as the Creeper virus. Systems infected with this virus displayed the message "I'm the creeper, catch me if you can." Since then, hundreds of thousands of viruses have been created that perform different types of harmful activity.
Computer viruses cause untold havoc, reportedly costing companies millions of dollars each year. The easiest way to protect your system from a virus is to invest in an antivirus program. Antivirus applications work as a shield and scan your system for any suspicious file or application.