Xbox Connection problem

[pharaoh3103]

I've recently bought an xbox 360 which initially connected fine to xbox live, wirelessly via my talk talk router. After a couple of days I was unable to connect. The problem is between the xbox and the router. I know the wifi is working because it can find the wifi signal when it scans for networks....it just won't connect to it.
My laptop still connects fine.
Please help me, I'm tearing my hair out!!