multiplayer problem

ok so im new to the call of duty games and i just downloaded call of duty 4 cracked version my single player works fine and i installed all of the patches for multiplayer but i doesnt work wen i try to refresh the servers nothing comes up ive tried downloading the crack for multiplayer and some one told me to plug in head phones but still no servers come up can some help me

the same thing happens to me but i bought the game

ya this game on the computers at school that happens
and i belive its the computer only thing i can think of cause we were getting the game from other computers and it worked on same but not others