LAN problems


When i click on a server to join it, it doesnt connect and gives me a "Operation is taking longer than expected, click ESC to cancel". If i cancel it or let it go until it says it lost connection, the game will freeze up and i have to turn off my computer by holding down the power button. BUT if I choose to connect to an internet game it works fine. I'm trying to sort out a LAN but I cant even connect to my own server on the computer that is running it!! I have tried everything at Microsoft and nothing works. All my drivers are up to date and i have Windows XP, the single player runs perfect. So if anyone could help me with this i would be very, very, very, very, very thankful!