Multiplayer issues

I am looking for some info/advice as to how to sort out a multiplayer problem my friend is having.To make things a little easier to understand, I thought I would put things in bullet points.1. My multiplayer works fine apart from the client built into FS doesn't seem to do anything when clicking find or search. Perhaps I don't understand how to use it properly.2. His multiplayer used to crash when clicking multiplayer in the FS menu. A reinstall has sorted that out.3. He can join MSN Zone games ok but when he gets in the game, he can't see anyone else and they can't see him.4. He has tried disabling all other programs including anti-virus.5. He is using the 9.1 update, SP2 and DirectX 9.0c.6. He has opened the correct ports in his firewall but doesn't know what to call them.I can't really think of anything else.Please help!Thanks very much.