Specifies whether this computer will receive security updates and other important downloads through the Windows automatic ...

"Specifies whether this computer will receive security updates and other important downloads through the Windows automatic updating service.

This setting lets you specify if automatic updates are enabled on this computer. If the service is enabled, you must select one of the three options in the Group Policy Setting:

2 = Notify before downloading any updates and notify again before installing them

When Windows finds updates that apply to this computer, an icon appears in the status area with a message that updates are ready to be downloaded. Clicking the icon or message provides the option to select the specific updates to download. Windows then downloads the selected updates in the background. When the download is complete, the icon appears in the status area again, with notification that the updates are ready to be installed. Clicking the icon or message provides the option to select which updates to install.

3 = (Default setting) Download the updates automatically and notify when they are ready to be installed

Windows finds updates that apply to your computer and downloads these updates in the background (the user is not notified or interrupted during this process). When the download is complete, the icon appears in the status area, with notification that the updates are ready to be installed. Clicking the icon or message provides the option to select which updates to install.

4 = Automatically download updates and install them on the schedule specified below

Specify the schedule using the options in the Group Policy Setting. If no schedule is specified, the default schedule for all installations will be everyday at 3:00 AM. If any of the updates require a restart to complete the installation, Windows will restart the computer automatically. (If a user is logged on to the computer when Windows is ready to restart, the user will be notified and given the option to delay the restart.)

To use this setting, click Enabled, and then select one of the options (2, 3, or 4). If you select 4, you can set a recurring schedule (if no schedule is specified, all installations will occur everyday at 3:00 AM). 

If the status is set to Enabled, Windows recognizes when this computer is online and uses its Internet connection to search the Windows Update Web site for updates that apply to this computer.

If the status is set to Disabled, any updates that are available on the Windows Update Web site must be downloaded and installed manually by going to http://windowsupdate.microsoft.com."

If the status is set to Not Configured, use of Automatic Updates is not specified at the Group Policy level. However, an administrator can still configure Automatic Updates through Control Panel.