Inspiron 1501 appearance

My Inspiron 1501’s appearance looks like Window’s 2000 (ME Edition). I am not particularly a fan of it and would like to make XP default, but every time I do it in “display” (after a reboot of my PC), it reverts itself. I believe this has something to do with “Crystal XP,” but I am not sure. How do I prevent this from reverting? (BTW: I am running on XP)