The Chernobyl virus is a computer virus with a potentially devastating payload that destroys all computer data when an infected file is executed. Since many files are executed during computer use, the virus is able to spread quickly and infect those files. The Chernobyl virus is the first virus known to have the power to damage computer hardware. The activated viral strain attempts to erase the hard drive and overwrite the system's BIOS as well.
The virus was detected as early as 1998, but its payload was first triggered April 16, 1999 - which was the 13th anniversary of the disaster at the Chernobyl nuclear reactor. Although U.S. and European computer users were affected, especially students and some businesses, most of Chernobyl's damage was wrought in Asia and the Middle East. Chernobyl actually is a variant of a virus known as CIH, the initials for the alleged author of the virus, Chen Ing-hau, a Taiwanese computer engineering student). Some CIH variants activate on the 26th day of each month, while others do their damage on April 26 or June 26.
CIH is sometimes referred to as a "space filler virus," referring to its ability to clandestinely take up file space on computers and prevent anti-virus software from running.
Users of Windows 95 and Windows 98 are more susceptible to the risk of contracting the CIH virus. It is under these programs that the virus replicates and becomes active. Users of DOS, Windows 3.x, Windows NT, Windows 2000 or Macintosh are not considered at risk.