ip address

Have you tried resetting or unplugging the router for a few minutes?

yes reset both router and modem waited around 15 mins still no joy was told by my mate (hes the one with the problem) that when he first got the router it would not let him go wireless until he told the router the mac address of all the laptops / xboxs as well as the normal secure stuff you have on wireless

Check you are using straight through ethernet cables and not crossover.
Check MAC address filtering is not switched on in router settings, and that DHCP is switched on, although resetting the router with the small round reset button on the back (as ferguj1 suggested) would normaly do this.