Security Updates
Security Updates At Home
Microsoft Security
Microsoft Security and Privacy
Using Windows Update
http://windowsupdate.microsoft.com
You may be prompted to download the Windows Update software. After the software is downloaded, click on a link to "Scan for updates".
A status window will appear as updates that are needed are determined.
Click on the link for "review and install Critical updates".
Click the "Install now" button to begin the download and installation of ALL Critical updates or choose to remove certain critical updates by reviewing each update and then clicking Install.
Since some updates must be installed alone, you may have to go through several cycles of rebooting the computer sometimes for all the updates to be processed.
To Schedule Automatic Updates
You can set up Windows to automatically download updates and install them on a schedule you specify. This enables you to keep your computer up-to-date without any interruptions. You don't even have to be at your computer.
Microsoft Articles
The following are some recommended "HOW TO" articles available from the Microsoft support knowledgebase to further assist you in the area of keeping your Windows computer secure and up-to-date:
HOW TO: Keep Your Windows Computer Up-to-Date (311047)
Description of the Automatic Updates Feature in Windows (294871)
HOW TO: Configure and Use Automatic Updates in Windows XP (306525)
HOW TO: Configure and Use Automatic Updates in Windows 2000 (327850)
HOW TO: Schedule Automatic Updates in Windows XP and Windows 2000 (327838)