This whole thread reminds me of a book I read a couple years ago called "Daemon" by Daniel Suarez.

"When a designer of computer games dies, he leaves behind a program that unravels the Internet's interconnected world. It corrupts, kills, and runs independent of human control. It's up to Detective Peter Sebeck to wrest the world from the malevolent virtual enemy before its ultimate purpose is realized: to destroy civilization."

http://amzn.to/132XgGv (affiliate link)