How download Call of duty and register

How can i download and register free on black ops PC? i have already on ps3 but i'll enjoy hacking in zombie ^^

black ops online on pc only work if you buy it.
the best you can its download black ops and put crack for sigle player campain.
and put this on call of duty black ops HELP!!!

Or play against bots in mp

you can not register black ops for free unless statted by others torrents/bots,

you either buy it for MP or you get cracked version.