Xbox 360 Problems

Ok, as the title says, I have an At&t 2wire 2701 HG-B wireless gateway (the 360 is just a normal Arcade and it was made in 2008 so no wireless card in it) and i’m having problems connecting to Xbox live on it. When i test the settings (i have an ethernet cord going from my laptop to the 360 and my laptop gets a wireless signal via the router) nothing works! The farthest i can get is to get the 360 to identify the connection as wired, but then the IP address test fails and it doesn’t continue from there. I have tried EVERYTHING to get this online. I have forwarded my ports for the 360 like i was supposed to and everything should be working but it’s not. The only thing i think that may have gone wrong is that my ethernet port on my laptop is notorious for being bad (it just won’t connect to my router, even if they if is plugged in and the internet is running perfectly). I’ve watched countless youtube videos about bridging the ethernet and wifi connections and tried the 2 methods that there are to try to get on live but nothing. I’ve played with the 360′s settings and tried every concievable combination at getting the right settings. NOTHING IS WORKING RIGHT! If anybody has had this problem or knows how to fix it, please help me. As of now, Halo 3 will hold my anticipation to get on live back, but i can only wait so long…. Thanks to anyone who helps