LOL these make me LOL..... If lagit you have a license agreement you have to login to your e-open account if it's VL to get key. And if you got it off torrent you will not get help here.
If you bought a copy from a store it is somewhere in the materials that came with it (usually on some fancy printed card from microsoft). If you don't have that talk to whomever you paid for the install..if you didn't pay someone for the install...well you will need to