All Windows versions

• Xenix (licensed version of Unix; licensed to SCO in 1987)
• MSX-DOS (developed by MS Japan for the MSX 8-bit computer)
• MS-DOS (developed jointly with IBM, versions 1.0–6.22)
  
  
  
  
  • Windows 1.0 (Windows 1 - Based on Visi-On) April 30, 1985
  • Windows 2.0 (Windows 2) May 25, 1988
  • Windows 3.0 (Windows 3 - Is the first version of Windows to make substantial commercial impact) August 29, 1990
  • Windows 3.1x (Windows 3.1) March 18, 1992
  • Windows 3.2 (Chinese-only release) November 19, 1992
• Windows for Workgroups 3.11 January 21, 1993
  
  
  
  
  • Windows 95 (Windows 4) August 24, 1995
  • Windows Chicago May 18, 1995
  • Windows Utopia June 19, 1997
  • Windows Plus! November 13, 1997
  • Windows 98 (Windows 4.1) June 25, 1998
  • Windows Memphis July 24, 1997
  • Windows Millennium Edition (Windows Me - Windows 4.9) September 14, 2000
• OS/2 (developed jointly with IBM) October 24, 1996
  
  
  
  
  • Windows NT 3.1 (OS/2 3.0 - Windows 3.1) March 31, 1994
  • Windows NT 3.5 (Windows 3.5) December 29, 1994
  • Windows NT 3.51 (Windows 3.51) February 8, 1995
  • Windows 95 64-Bit Edition March 20, 1997
  • Windows NT 4.0 (Windows 4) February 21, 1996
  • Windows 2000 (Windows NT 5.0 - Windows 5) February 29, 2000
  • Windows XP October 22, 2001
  • Windows Whistler December 28, 2000
  • Windows V-smile July 13, 2006
  • Windows Neptune November 10, 1999
  • Windows Odyssey April 5, 2001
  • Windows Trident September 11, 2001
  • Windows Server 2003 October 28, 2003
  • Windows Fundamentals for Legacy PCs March 24, 2005
  • Windows Vista January 26, 2006
  • Windows Home Server April 19, 2007
  • Windows Server 2008 September 29, 2008
  • Windows 7 October 26, 2009
  • Windows Preinstallation Environment (WinPE) April 13, 2009
• Windows CE (OS for handhelds, embedded devices, and real-time applications that is similar to other versions of Windows) May 30, 2002
  
  
  
  
  • Windows CE 3.0 December 25, 2002
  • Windows CE 5.0 February 27, 2003
  • Windows CE 6.0 May 5, 2004
  • Windows Mobile (based on Windows CE, but for a smaller form factor) April 14, 2005
• Singularity - A research operating system written mostly in managed code (C#) November 30, 2009
• Midori - A managed code operating system July 21, 2010
  
  
  
  
  • Xbox and Xbox 360 OS custom operating systems May 12, 2005 and August 10, 2006