Wireless Connection Issues

I'm trying to setup wireless for a friend of mine. They have cable internet currently which they access through a Motorola SB51000 SURFboard Cable modem. They got given a D-Link DSL-G604T wireless router. The Motorola modem is currently plugged into the 2nd Lan port, the 1st lan port is plugged into the desktop PC. The desktop can surf fine, and the D-link is broadcasting a signal fine which the laptops in the house can see. But the wireless signal is not allowing internet access. Any suggestions on how I can get the D-Link to broadcast an internet signal would be much appreciated.

Also I got into the modem settings for the D-Link(10.1.1.1 - when only the D-Link was plugged into the PC without the motorola plugged into the D-Link) and set a wireless password and i read on another forum to clone to MAC address (which looks like it did) and to turn DHCP off which I did.

Many thanks in advance.

I think you have a problem of frequency in there, so you should try out with other hardware in the network. If it is still in the same condition then that is fix, you have a problem in the broadcast media. So check the router also. I hope you will find the problem.