CIH (1998)Check it out over here.
Estimated Damage: 20 to 80 million dollars worldwide, countless amounts of PC data destroyed
Unleashed from Taiwan in June of 1998, CIH is recognized as one of the most dangerous and destructive viruses ever. The virus infected Windows 95, 98, and ME executable files and was able to remain resident in a PC's memory, where it continued to infect other executables.
What made CIH so dangerous is that, shortly after activated, it would overwrite data on the host PC's hard drive, rendering it inoperable. It was also capable of overwriting the BIOS of the host, preventing boot-up. Because it infected executable files, CIH wound up being distributed by numerous software distributors, including a demo version of an Activision game named Sin..
Top 10 most destructive virusses
Posted on Friday, July 07 2006 @ 9:14 CEST by Thomas De Maesschalck
TechWeb takes a look at the ten most destructive computer virusses: