can't connect to the Network, ive tried ...

My new router is a Belkin Wireless G , Model # F5D7234-4 v4 . Thats connected to my PC and dsl modem. Downstairs connected to my xbox is a linksys music bridge, ethernet cable into the xbox, power cord into the wall. My old belkin router worked great, till it started smoking due to my retardness of putting in the wrong ac adapter into it. But im getting conserned, ive tried auto connecting to my router w/the xbox, nothing. I've tried manueling entering everything , nothing. Could me having two yellow cords upstairs have anything to do with my problem? Cause before I remember having one blue cord and one yellow one. I spent 2 hours on the phone w/microsoft and they could not help me. Then another hour on the phone with belkin. They even opened up all the router ports. Still nada. Keep getting the message '' cannot find the ip address'' or something. I am so frustrated...god modern warefare 2 and a new router and the damn thing wont connect! Whoever helps me figure this out will be my hero can't connect to the Network, ive tried ...
ok first lets run threw all the simple stuff first have you tried hooking this up to a computer?did it work?how far is your router from your router?and another question did you mean to have a router linking to another router?how much floor are we talking about that is separating you from the other router.id hate to ask you to return it if you can and try picking up an adapter, but i think you would get better results, but theres no reason the router should not be working at all.so get back to me and i'll try to help as much i can can't connect to the Network, ive tried ...
no i havent, my pc moniter doesnt have AV inputs.my router is downstairts, while my other router is upstairs, worked before with the old router just fine. alot of floor , stairs, and a kitchen, no way of hardwiring.
Hi, I wanted to reply because I am having the same problem. XB360 connects to other games, but with this one game, it will not find online games to connect to, it thinks the NAT is strict. whoel house runs through it and router works great....just this one game. Any thoughts?