halo 2 (pc version) multiplayer not working, HELP!?!??!?!?

[Unknown 2 U =)]

when i click on network for halo 2 pc versions multiplayer games to open up, halo 2 says the port is being used.
whys this?
how can i fix this?
it says: you cannot play with others because the network port is in use. the game or server may already be running.

just installed today btw

 

[Herwan]

reinstall it and if cannot contact halo

 

[Scarface]

if you have a game client then delete it and download again i tried it or u can download the halo 2 client from another site say www.cnet.com