When was Microsoft Windows first released?
Microsoft Windows version history
November 10, 1983
 
Microsoft Windows was announced by Bill Gates on November 10, 1983.[1] Microsoft introduced Windows as a graphical user interface for MS-DOS, which had been introduced a couple of years earlier. In the 1990s, the product line evolved from an operating environment into a fully complete, modern operating system over two lines of development, each with their own separate codebase.