Why Won't "Welcome To Windows" Show Up During OS Install?

Sometimes when I do a clean install of XP, it doesn't bring up the "Welcome to Windows" setup where you turn on automatic updates, tell how the computer will connect to the internet, and set up the user accounts. Why does it sometimes skip this step? When it skips it goes straight from the XP installation to loging into the Administrator account. It doesn't always do this, but it often does. I'm not doing anything different on the different reinstallations. What's going on?

Thanks.