PLEASE HELP!!! AIRPORT EXTREME IS GREEN BUT NOT CONNECTING TO INTERNERT!!!

Please, I'm begging of fellow man, women and children to help me figure this out!

What Happened:

I had my Internet and everything working before I went to work at 3 PM. My girlfriend got home around 4 PM and all of a sudden the my Internet was not working. I had to call my ISP, Comcast, and we had tested Internet connectivity which worked perfectly fine which is how I am typing this now. After that, I looked up some things that would remedy the situation. Power cycling the modem for minutes, seconds and hours. Also, I have tried to plug both the modem and router without plugging any Ethernet cord in to both of them, wait for them to power up, hook up the Ethernet cord and nothing. I have done factory resets on both the modem and routers and created a totally new network to see if that was the problem and noting. I have also changed the IP addresses, Subnet Masks, Router numbers, DNS servers and Domain names and nothing. I was stupid and did not get a protection plan on it, and my warranty JUST expired a couple of weeks ago, so I have barely had this router for a year. As all indications go, it is saying that it's connecting to the Internet, but when I go to my Macbook Pro and check the system preferences it's saying its connected to the airport, but when I do the assist me function and go to diagnose or assistant and test everything, the Internet and Server are yellow and everything else is green. I DON'T KNOW THE ISSUE!!!

Hardware:

Modem - Motorola Surfboard: Model SB6121

Router - Apple AirPort Extreme 802.11n Wi-FI

Any and all advice would be greatly, greatly appreciated. I do not want to have to purchase a brand new router after just purchasing this one last year for over $150. I'll be eagerly awaiting your help. Thank you in advance.