Question : Cannot connect to cable modem directly or through router.

I am having a problem with my new Toshiba A200 laptop connecting to the internet either through a direct connection to the Motorola cable modem, or through the router Dlink 514.  Both the ethernet and wireless ports give me valid assigned 192.168.0.X ip addresses through the router.  The wan connection however does not get a ip address or dns.  When I connect the laptop directly to the cable modem through the wired ethernet port, I get an automatic ip adresss 169.X.X.X.  The lights on the ethernet port and the pc activity light on the cable modem BOTH work.  My roommate had his MAC laptop connected to cable modem directly before and it worked 100%.  We are overseas right now, and communication with the internet company is very difficult.  I was having difficultly releasing and renewing ipadresses before, getting "this operation requires elevation", but I think I have that sorted out. Any ideas?

Answer : Cannot connect to cable modem directly or through router.

If neither the router nor the laptop is receiving DHCP, lets focus on the laptop with no router.

Turn the laptop off.
turn the modem off
--> Wait 2 minutes
turn modem on & allow it to fully ramp
turn laptop on

Are you online?

You stated you are pulling a local IP (192.168.0.0 from the router) - so you're laptop seems fine... so I'd suspect the modem side. Two options:
1) locked in on the Macintosh MAC-address
2) not transmitting lease info

The Macintosh worked fine, so unless something changed -- You likely need a reboot on the modem. You can also try accessing the modem's page and post the signal information. Try 192.168.100.1

On occassion, UBR's will fail to release a MAC-Address. this would require a call to the ISP. They can telnet into the UBR and clear the MAC addresses from your modem.

Short of this -- post your IPCONFIG info as suggested by savone