I'm a little confused as to how you have everything set up currently.

Optimally, it should be like this:

The LAN/Ethernet port on the modem should be connected to the WAN port on the router. Any non-wireless computers should be connected to the normal LAN ethernet ports on the router. Any wireless computers should be connected through wireless using the correct settings.

If things are not working in that fashion, power everything down. Then connect the power to the modem and wait until it's completely ready. Then connect power to the router and wait until it's completely ready. Then, turn on one of the computers (preferably one that is connected directly to the router with a cable). See if you can open the router's control page in your browser and if you can get an internet connection.

After all is working thus far, try connecting with a wireless laptop.