Windows XP Service Pack 2 includes a firewall, automatic updates and antivirus notification pop-ups that display frequently when there is a problem with your computer. These security alert pop-ups display when anti-virus programs are uninstalled or disabled on your computer, when your system is not updated and when the firewall is disabled. Sometimes they can be a great nuisance because they display too frequently. If you don’t want these frequent notifications, you can stop them easily from the Security Center.
Click the Windows "Start" button and click the "Control Panel."
Double-click the "Security Center" icon and click "Change the way security center alerts me" on the left panel.
Remove the check from the alert settings you wish and click "OK" to save the changes. Close the Security Center.