How to install SP2 when you don't have a valid windows XP version?

[Neos]

SleepWaking said:
just download xp sp2 on torrent site. (pls warn me if this is against forum rules). I bought windows vista so i could play crysis :P, i wanted the genuine version becouse i wanted to know for sure it would update and run properly :P

 i also downloaded it through torrents, but it won't allow me to install it.. that's the case.