How to turn off the Windows XP SP2 Security Center Alerts ?
To turn off Security Center Alerts:
Navigate to Start -> Control Panel -> Security Center. Click on "Change the way Security Center alerts me" and clear the check boxes for items for which you don't want to receive alerts.
* If the PC is part of a domain, security settings are probably managed by the sysadmin, and the Security Center does not display security status or send alerts.
* The Security Center can also be disabled from "Services" if you'd like it to stop checking and alerting you all together.