Are you running H2 Shark to play Halo 2? The servers at the very top of the browser list between Double Team - Team Snipers require it since they are ranked games. Are you having trouble connecting to those or just any game in the list?
Yea I downloaded the launcher which is v3 now I think. Yeah I've tried to join any game but no luck. I made a thread on the help section and someone said about having the correct PCID?