Xbox live keeps saying error

Hello,
We set up our xbox and hard wired it to our router. We are able to get online and it says the NAT is correct. We went online with the computer and our account says that it is all up and running including the gold membership. I even connected my computer to the xbox via router and wifi on the windows 7 computer and listened to music.
Problem is, every time my son tries to play halo live it puts up a error notice that the Halo Reach server is down and to try again later. Very frustrating. The xbox plays fine at a friends home, just not ours? Could it be our older Iogear router? The router works fine for everything else even Netflix.

Thanks in advance.
I am so flustered after working on this with my son and his friends for a couple days...
going thru all the technical stuff on the xbox live site to set up. Still not working?

Any advice would be much appreciated.
Thanks again,
frazzled mom