Beginning March 19th, Microsoft will be automatically rolling out Windows 7 Service Pack 1 to users via Windows Update, which previously was an update that would require the user to install themselves. Now, the choice is no longer there.
"Starting tomorrow, Windows 7 Service Pack 1 (SP1) will begin rolling out automatically on Windows Update. Updating customers to Windows 7 SP1 is part of our ongoing effort to ensure continued support and improved security updates for customers who have not yet installed SP1," Microsoft stated in an official blog post. The installation of the Service Pack will be fully automatic and no user action will be required for those who have Automatic Update enabled.
It has also been two years since the official release of Windows 7 Service Pack 1 and Microsoft would like to remind those who are still running Windows 7 (without SP1) that the operating system will no longer be supported starting April 9th of 2013. If you are running SP1, you are still good for a while.