Hang on: if you use "bit torrent" or other file sharing network to download a copy of XP, then install this on a new or re-harddrived machine, then validate ths copy with the original XP serial number from the old, scrapped machine or the serial number on the case of the machine with it's new hard drive, what is illegal in doing this?
It is only illegal if you validate with a "dodgey" serial number.
P.P.