go to below site and take WinXP expert quiz and if all answers are correct, you can download a Halo theme for WinXP

<a href="http://www.microsoft.com/windowsXP/expertzone/quiz/default.asp" target="_blank">http://www.microsoft.com/windowsXP/expertzone/quiz/default.asp</a>

BTW - if you are lazy and dont really want to take the test the answers are as follows:

E,E,D,A,C,E,B,A,A,C,A,A,A,E,D