How come I cannot connect to xbox live?

Q: I can’t connect to xbox live. Tried everything, resetting the modem, using the right WAP and all that it’s told me to do. It worked perfectly fine on Monday without a hitch.

I’m using a Netgear DG834v2 router and I used a tutorial to make sure I could connect. The wireless adapter on my xbox has a flashing green light, which sais to me it’s trying to connect but something is stopping it.

Can anyone help me out? It’s getting a little frustrating as I don’t know what’s wrong with it.