Windows XP Service Pack 2 (SP2) added the Security Center, which centralize most security-related functions to one control panel. By default, if it finds a problem it will start nagging you to fix it. For example, if you turned off automatic updates or it doesn't recognize your anti-virus application. Here is how to turn off this feature:

    * Open the Control Panel folder
    * Open the Security Center control panel
    * In the left pane, click the link labeled "Change the way Security Center alerts me"
    * Uncheck the item(s) that it's complaining about (i.e.: firewall, automatic updates, or virus protection)
    * Press the OK button.