Windows Security Center

• A main component of Service Pack 2 for Windows XP was the addition of a "Windows Security Center," a way for the user to be notified of general security issues affecting the system, including antivirus software, Windows Update requests and Firewall information.
  
  

Windows Firewall

• Windows Firewall prevented unwanted connections to the system by blocking by default all machines not on the local network. This update made the system less vulnerable to attack and allowed the user control over which connections to allow.
  
  

Wi-Fi Networking

• Though wireless networking was around before Service Pack 2 was released, SP2 greatly increased the ability of users to set up and control wireless connectivity with features like the "Wireless Network Setup Wizard." New security encryption protocols like WPA (Wi-Fi Protected Access) were also added.
  
  

Internet Explorer Update

• Internet Explorer 6 received some updates with Service Pack 2, such as pop-up blockers and some needed security enhancements. Internet Explorer began to receive its own service packs soon after.
  
  

Cosmetic Updates

• The boot-up screen prior to Service Pack 2 was different for each Windows XP edition. Professional loaded with a blue bar, Home Edition loaded with a green bar, and in embedded systems, the bar was yellow. After SP2, all editions loaded with the same blue bar.