The service pack fixes a number of problems in the original release of XP as well as adds security updates. Follow the step:

Purchase the Service Pack 2 disk from Microsoft & Back up all important information to CD.

Insert the Service Pack 2 disk into your CD or DVD drive. The upgrade should begin automatically. If you downloaded the file, browse to the location where it is stored on your computer. Double-click on the file and the process will begin.

Follow all onscreen instructions. When the process is complete, the system will automatically re-start.

Check to make sure the upgrade is recognized by the system after the re-start. Click on "Start" and then "Control Panel."

Click on the "System" icon. Click on the "General" tab to confirm that your system is now running Service Pack 2.