Microsoft Corporation formally announced Microsoft Windows  − 10 November, 1983

Submitted by: Micah Heins Fall07

"On November 10, 1983, at the Plaza Hotel in New York City, Microsoft Corporation formally announced Microsoft Windows, a next-generation operating system that would provide a graphical user interface (GUI) and a multitasking environment for IBM computers."

http://inventors.about.com/od/mstartinventions/a/Windows.htm