Below is a list of Microsoft's desktop operating systems, and their release date.
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October 1985 - Windows 1.
December 1987 - Windows 2.
May 1990 - Windows 3.
August 1995 - Windows 95.
June 1998 - Windows 98.
February 2000 - Windows 2000.
October 2001 - Windows XP.
November 2007 - Windows Vista.