I know that to upgrade to SP3, you need either SP1 or SP2. But can I install SP3 using the disk then updating to Bootcamp 2.1 meaning I do not need SP1 or SP2?
If your Windows XP disk comes with SP3 then there is no need to install the previous SP just make sure the disk you have is the actual operating system disk and not simply an update disk because that won't work.