XBOX 360 Isn't connecting to XBOX LIVE- Help me ASAP Please!?

I have Bran New XBOX 360 Elite, and I have wireless connection, plus my modems on the other side of the house, so what I do is connect the wire to the back of my XBOX and to my LAPTOP, But no-matter what I do, XBOX LIVE Won't connect, all lights are on, i've tested the internet, reset the xbox, and restarted my computer, It won't workk! Help me please, in details!