Installation with Bootcamp

I have already installed Windows XP on my Macbook (Leopard) with Boot Camp. I would also like to install Parallels. When I install it, it says installation complete. However, when I start Parallels it goes into the Windows XP start up screen and then automatically proceeds to restartup over and over without my interfering. So I get the startup screen over and over but no Windows XP actually booted. What am I doing wrong? Thanks.