Why cant i get wifi to work?

Okay so i have a linksys wireless router. I connected the router to the computer and the modem to the linksys router, though when i conect it to port 1, its says theres no internet, though when i conect it to port 4 it says there is. But then i go to get on the internet and it says im not connected, though on my ipod i can see the signal and even start connecting but nothing will load. I tried Reseting the wireless router, i switched around cables. None of my cables are broken. So whats wrong? I'm running windows xp, how can i fix this?