Eliminating the possibility of a connection error as PC's connected, XBOX connected via Modem, which left the router configuration.
Tried combinations of, changing the MTU setting on my Belkin router to the 1364, - SAME ERROR CODE
Opened the ports 88 (UDP) 3074 (UPP&UDP) 53 (UPP&UDP) and 80 (TCP) - SAME ERROR CODE
Made a static IP address on PC and manually change XBOX setting to match - SAME ERROR CODE
Manually entered the DNS setting and Subnet Mask - SAME ERROR CODE
Updated the Firmware on the Router - SAME ERROR CODE
Enable UPnP ( Universal Plug and Play) - SAME ERROR
I found this info... http://www.noddegamra.co.uk/problems-with-xbox-360-live-nat-settings/3/ THIS WORKED...Static IP Address and DMZ
The XBOX 360 network settings allow you to give your console a static ip address. In this case, select something like 192.168.2.27
Back in the Belkin router’s administration pannel, there is a feature called “DMZ” listed under thefirewall settings. It is here that will allow you to select one local ip address to be placed outside of the NAT settings of the rest of the network. Please note that I only recommend this feature for your XBOX 360, never use it for a PC ip address unless you want to be left open to hacking attacks.
Once you have applied these changes, I recommend that you restart your router (and possibly your XBOX 360) before testing your connection again.