I found the real manual here,
Second one down.
Are you using Cable, or DSL. DSL requires you to setup a PPPOE connection, putting in your Username and password for you DSL connection.
Are there any other routerrs on the network? Just making sure you are not trying to use the router then there is one already one on the work.
I would suggest your use the reset button on the back, resetting it to defaults. That way, you should be able to plug in your modem to the WAN port, plug your computer into the LAN port.
Then restart the modem, wait 2 min, power up the router, wait 2 min, and startup the PC. Make sure your IPs are set to automatically get IPs and DNS. The router's DHCP should supply them to your PC.
DSL requries you setup a PPPOE connections, which really just consists of selecting the pppoe option, putting in the infomation, and the doing all the rebooting.
It you still are having issues, get back with us!