Windows 7 Service Pack 1 (SP1) was announced on March 18, 2010. A beta was released on July 12, 2010. The final version was released to the public on February 22, 2011. At the time of release, it was not made mandatory. It was available via Windows Update, direct download, or by ordering the Windows 7 SP1 DVD. The service pack is on a much smaller scale than those released for previous versions of Windows, particularly Windows Vista.
when was windows 7 service pack 1 released
February 22, 2011