The screen above is showing you two windows users. You can have as many as you want. Many users do not bother about creating more then one accounts. While installing windows XP, user is asked about administrator password. Some users provide password and some not. In case you have not given administrator password and created another windows user. Suppose you forgot user’s password then you can always Ctrl+alt+Del twice at Logon screen to switch between Log On Mode which will bring prompt asking you user’s name and password. Write administrator in user input box and press enter. You are in. That is ok.