Automatic Updates is a mechanism with an awkwardly plural-sounding name by which Microsoft or corporate network managers distribute critical security updates to Windows users. Fixes sent by this means are considered so important for adequate security in the hostile Internet environment that Microsoft prefers that you configure it to download and install the updates, and if necessary even restart your computer without your being aware of it.

There are four levels of Automatic Updates protection to which you can subscribe:

• Automatic Windows will query Microsoft or your corporate network servers every day or on a specified day of the week, or whenever Internet access is available, will download the updates when they become available, and will install the updates at a designated time, if the computer is on at that time, or the next time you shut the computer down, or when you log on as a Computer Administrator and open the Update Notification icon in the taskbar, whichever occurs soonest. This is the option recommended by Microsoft.

• Download updates Windows will download the updates automatically, but will not automatically install them until you ask for them to be installed. You will be prompted to do this when you log on as a Computer Administrator; a balloon tip will pop up from the taskbar informing you that updates are ready to install.

• Notify me Windows will not download updates automatically. You will have to log on as a Computer Administrator to receive the pop-up notification that updates are available for download and activate the pop-up icon to begin the download process.

• Turn off Windows will neither download nor notify you of the availability of updates. This option should be used only on a corporate network where the administrators will take responsibility for all updates, but no Automatic Updates server is installed locally.

In most cases the Automatic method is best, for as long as your computer is turned on and has frequent Internet access, you will get these critical security fixes within hours or days of their release. The Download Updates option is recommended only if your computer is running important services and cannot be allowed to shut itself down for a restart without your consent and supervision, and you will be sure to log on as a Computer Administrator frequently so that you see the update notification; or, your computer is not connected to the Internet so is not vulnerable to the attacks that these fixes are designed to ward off.

To modify the Automatic Updates settings, right-click My Computer and select Properties to open the System Properties dialog. Select the Automatic Updates tab, and make the appropriate selection. Click OK to save the change.

It is quite important that the vast majority of Windows computers do use Automatic Updates so that in the future there will not be large numbers of unprotected, vulnerable computers for software viruses and worms to prey upon. Keeping the number of vulnerable systems under a certain "critical mass" will help minimize the number of virus storms that occur.