LAN not working for any games?

I can connect anywhere but when i set up a LAN server on games (Minecraft, CIV4 etc…) it will not work i read that on minecraft you can't use the same username so i thought it was that tell i tried to play on CIV4 and that did not work for my buds we went to another house and it worked so it is the LAN not the computers

No, LAN is a Network which refers "Local Area Network".

If you are behind a firewall or router, you need to open the ports for your games in order to play.