Anyon with techno know-how please help us?

Alright, I have limited techie knowledge, but the situation is this: our internet works fine when the computer is plugged in directly to the Rogers modem, but as soon as I hook up the D-link router (which has worked more or less flawlessly for the past two years) I get a message telling me that "a network connection is unplugged" and no one can access the internet.

All of the cables are clearly plugged in. I've reset the bloody thing at least twenty times, and before you ask YES it is turned on, and all the lights are on too. I changed the cables.

Any idea of why this might be happening? The lack of wireless is driving us up the wall, and I don't want to have people invading my room to check their emails for the next six months.