cod4 helpme

i recently reformated my pc and reinstalled cod4 but when tis done downloading and confirmign evenrything it says something about being unable to secure a firewall... sumthing and i dunno wut to do with that. and when i click *ok* a couple hundred times it passes threw and its complete... when i click the multiplayer or single player icons it says " dirrectx has encounterd an unrecoverrable error. click the readme for possible solutions.. but the readme doesent help at all.. i downloaded latest directx... WTF IS WRONG plz help i would appreciate it and i dont have xfire if u think thast the solution