Be careful what you swear to. You state that you are using XP Pro because it doesn't require activation. I beg to differ. XP Pro actually does require activation and also "re-activation" if you need to reinstall it. If you have not been through the activation process yourself with XP Pro, I would venture to guess that it came pre-installed on your machine. Most OEMs pre-activate the OS at the factory so the retail customer will not have to do it themselves.

I would suggeest you try to reinstall XP Pro and if you can do so without activation, then your comment is valid.