The Windows Vista version of the Security Center deals with the Firewall, Automatic Updates, Anti-Virus and Anti-Spyware (Malware) protection, and other items.
If the Security Center senses that one of these items is outdated, not configured, or not installed, the yellow Security Center icon is displayed in the notification area.
If you want to prevent the Security Center icon appearing:
1. Start / Run / Rundll32.exe %SystemRoot%\system32\shell32.dll,Control_RunDLL "%SystemRoot%\system32\wscui.cpl",Security Center / OK2. Press Change the way Security Center alerts me.
3. Select Don't notify me and don't display the icon (not recommended).
4. Press OK.