Since I wrote the note below, I have found that I cannot start my macbook in Leopard but can start it in windows. I don't know if it is related but will post what I find.
Hi all, If you are running bootcamp and intend to install windows xpsp3, you will need leopard to do it since there is an update to bootcamp that needs to be installed on the windows side before xpsp3 will work properly. I installed xpsp3 on my system running leopard with bootcamp just fine. -- Jonnie Appleseed With His Hands-On Technolog(eye)s Reducing Technologies disabilities one byte at a time
