Xbox live connection issues

Hi there. My friend has an Xbox 360 that has some issues connecting to Xbox Live and I was wondering if anyone had some suggestions to help. He uses an ethernet cord to connect to the internet but everytime he plugs it in and tries to sign in it says "your console can not connect to xbox live" and then comes up with an error code. We tried my wireless adaptor but the Xbox couldnt connect to the modem. 

Any suggestions on a fix?

Thanks everyone.