Xbox 360 slim wireless connection.?

well heres the problem. i got a xbox 360 slim the new sleek black one? well i have been able to go online freely play red dead online mw2 online and such games like that. i hadnt played it in about 2 weeks because i was playing with my ps3 online and my friend gave me a loan of brink for the xbox so as usual i plug in the HDMI into my tv boot up my xbox as normal BUT i dont sign into live.. i just sign in as my account but no things like what should show up if you have live. I got to my xbox and it says disconnected xbox live so i go into thereand connect and error i have to run a test i press ok it scans network and dosnt find one. if you imagine the stages (xbox 360 then your wireless bars then internet then xbox live) it dosnt connect to the Bars if you get me? its the network that failed. HELP ?