Windows service packs

The following is a list of service packs for Microsoft Windows:

Windows NT 4.0

 * SP1: 16 October 1996
 * SP2: 14 December 1996
 * SP3: 15 May 1997
 * SP4: 25 October 1998
 * SP5: 4 May 1999
 * SP6: 22 November 1999
 * SP7: August 2001

Windows 2000

 * SP1: 15 August 2000
 * SP2: 16 May 2001
 * SP3: 29 August 2002
 * SP4: 26 June 2003
 * SP5: 2004?

Windows XP

 * SP1: 9 September 2002
 * SP2: 25 August 2004
 * SP3: 21 April 2008

Windows Vista

 * SP1: 4 February 2008
 * SP2: 26 May 2009

Windows 7

 * SP1: 22 February 2011

Starting with Windows 8, service packs were phased out in favor of more regular updates distributed through Windows Update.