ok a couple of things

1)as said you both need to have the patch installed

2) and please I am not making any allegations but you also both need to have legitimate copys of the game and DVD - ie not 1 legit and 1 image or anything like that


if either then you will not be able to see the other game in the lobby

3) finally check you windows firewall and antivirus and make sure they are allowed as exceptions or turn them off completely


hope this helps