When you install Critical Update Notification, you give Windows Update permission to scan your computer (much like the scan performed by the Product Updates catalog). The scan, which occurs in the background while you are using the Internet, determines if the available update is appropriate for your system. Task Scheduler controls the scanning schedule, so you'll see a task for Critical Update Notification among your other scheduled tasks. The scanning schedule is preset and Microsoft recommends that you do not modify the settings. You won't be notified of every scan, the scans won't interfere with your Internet computing, and none of the information gathered is sent to Microsoft or sent over the Internet.

Before using Critical Update Notification at work, ask your network administrator whether this service is recommended for use within your organization. If your internal network requires you to enter a password each time you visit an Internet site, Critical Update Notification may require that password once a day in order to check for new updates.

How to download and install:

• From your Start Menu, click Windows Update.
• On the Product Updates page, select the check box next to Windows Critical Update Notification.
• Click the Download button at the top of the page.
• Follow the instructions on your screen.
• Windows Update downloads and installs Windows Critical Update Notification automatically.

How to use:
You don't need to do anything after downloading. Critical Update Notification works automatically. The scan runs in the background when your computer is connected to the Internet: The next time a critical update is available you will be notified. Scanning and Critical Update Notification only occur when your computer is connected to the Internet.