On March 12th, 2013, Microsoft issued 7 security bulletins. These bulletins have the severity rating of critical and important and are for Microsoft Windows, Office, Internet Explorer, Server Software, and Silverlight.

If your Windows system is set to "Automatic Updates", no action is required as your system will be updated when you connect to the Internet. If you do not have "Automatic Updates" enabled, visit:

Applies to Windows 8:
Windows automatic updating: Frequently asked questions

Applies to Windows XP, Vista and 7:
How to configure and use Automatic Updates in Windows

When you enable "Automatic Updates", Windows routinely checks the Windows Update Web site for high-priority updates that can help protect your computer from the latest viruses and other security threats. These updates can include security updates, critical updates, and service packs.

Depending on the setting you choose, Windows automatically downloads and installs any high-priority updates that your computer needs, or notifies you as these updates become available.

For More Information:

Microsoft Security Bulletin Advance Notification for March 2013
http://technet.microsoft.com/en-us/security/bulletin/ms13-mar