Make sure you plug the router to the modem. Now unplug the modem power and plug it back in. After all lights on the modem are restore to their original status, go back into the router configuration page and go to the Status tab.
In the LAN section, does it say DHCP enable or disable? Because it should be enable. If it's not enable go to the Home tab and under the section "DHCP Server" make sure you enable it, click apply to save. Go back to the Status tab.
In the WAN section, click DHCP Release then DHCP Renew and make sure you got an IP from the modem.
And you should be fine and should be able to connect to the Internet. Make sure the computer that you manually assign the IP address is set back to automically obtain an IP address and DNS address.
Every other setting can be found at this site:
http://support.dlink.com/faq/view.a...524 / DI-524_revC / DI-524_revD / DI-524_revE