1.There are 2 service packs available for XP. Assuming that you have
an original XP O/S. 2. YOu can go to device manager, click on the
General tab you will see the XP pack that you are having, or can go to
the SYSTEM in the control panel and see there. 3. These critical
updates/patches is to protect your system from spyware, virus, etc.
Need more information let me know.