Windows 7 Service Pack 1 (SP1)

What's included in Windows 7 Service Pack 1 (SP1):

Windows 7 Service Pack 1 (SP1) 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. Installing SP1 helps keep Windows 7 up to date. Applies to all editions of Windows 7.

Learn how to install Windows 7 Service Pack 1 (SP1):

How to get SP1

The recommended (and easiest) way to get SP1 is to turn on automatic updating in Windows Update in Control Panel, and wait for Windows 7 to notify you that SP1 is ready to install. It takes about 30 minutes to install, and you'll need to restart your computer about halfway through the installation.

To learn if Windows 7 SP1 is already installed:

Click the Start button , right-click Computer, and then click Properties. If Service Pack 1 is listed under Windows edition, SP1 is already installed on your computer.

Disk space requirements

Make sure you have enough free disk space to install SP1 (even though much of that space will be reclaimed after the installation).
Installation method and  Estimated amount of free disk space required

Windows Update   
x86-based (32-bit): 750 MB
x64-based (64-bit): 1050 MB

Downloading SP1 from the Microsoft website   
x86-based (32-bit): 4100 MB
x64-based (64-bit): 7400 MB

Installing SP1 using an installation DVD   
x86-based (32-bit): 4100 MB
x64-based (64-bit): 7400 MB

For general information about service packs, go to the Service Pack Center webpage on the Windows website.