Strange connection issues...

On your PC, go to the command prompt (msdos thing) and type "ipconfig /all" in the setup where you are connected to the dlink router.
Print Screen that shit, or copy it into [code] tags for us to see.

Also, don't have both the ethernet and wireless enabled and connected to your router.

Jam it back in, in the dark.

Okay, sorry I haven't gotten back to you on this.

Can you ping google from behind the router?
(ping www.google.com)

If not, can you ping 209.85.225.99?

Also, what are the specific models of your modem and router?

How ya doing, buddy?

Ok, well I asked you to ping google aside from that one ip address (and in retrospect that was actually a poor address to ask you to ping, my bad)
Please ping all of the following:

www.google.com
8.8.8.8
192.168.1.1

And just let us know if the pings get through, or whether they time out; no need to copy all the text.

Also, I find it highly unlikely that its a wireless protocol incompatibility issue. If the router were configured to accept n protocol exclusively while he is using g, he will not obtain an IP address through DHCP from the router, as the ipconfig readout indicates he has.

Furthermore, ignore everything about channel number and wireless. It is apparent that the problem does not lie in the physical layer.

Finally, did this router ever work for you?

This thing is sticky, and I don't like it. I don't appreciate it.