I just stumbled upon this answer which suggest to use "Windows XP Ultimate", which is in fact a Windows XP System modified by a Third-Party (read: Not Microsoft).
I'm not sure about possible implications, since I don't know as what such Third-Party-Builds are considered if it comes to 'Warez'.
So, what to do with it? I know that illegal actions of any kind should be flagged and punished...but I have no idea where to place this nor if it is an illegal or off-topic action. So the basic question is, are Third-Party-Builds of Windows/MacOSX are considered illegal, or not?
Edit: It seems like that is considered illegal because WPA and CD-Key-Activation was removed, though, that's a little thin because my arguments about torrents come to mind. You can still install Windows XP Ultimate and own Windows XP, so technically it wouldn't be illegal...difficult.
Edit2: The linked answer is gone.