Microsoft released the first official service pack for Windows 7 today. This is an important update that includes previously released security, performance, and stability updates for Windows 7. SP1 also includes new improvements to features and services in Windows 7, such as improved reliability when connecting to HDMI audio devices, printing using the XPS Viewer, and restoring previous folders in Windows Explorer after restarting.
There are different ways to install Windows 7 SP1. But before you start downloading, please note that you may need to keep from 750MB to 7400MB of free space (depending on the version of Windows) on your Windows partition to be able to install it. Also check if your Windows 7 is already updated to SP1. You can find this by looking under System in Control Panel, next to System type.
The easiest and safest way to install SP1 is using Windows Update service. If you use this, then your total download size will be 750MB for 32-bit Windows 7, and 1050MB for the 64-bit version. For this, you need to click Start, click All Programs and click Windows Update. In the window that opens, click “Check for updates” on the left. In the list of updates, you will see Service Pack for Microsoft Windows (KB976932), select it and click OK. Click Install updates to start downloading and installing the update. Enter your administrator password if prompted for the same. This method requires your computer to remain connected to the internet while the update downloads and installs.
The second way is to download the from the Microsoft Download Center. Choose the version of SP1 according to your Windows version and click Download. Run this downloaded file to install SP1.
There is also a provision to order a DVD from Microsoft containing SP1 from here, but it is valid only for users living in U.S. or Canada.
Please note that Geniune Windows validation is required to be able to download Windows 7 SP1.