What is the cable plugged into? Is it plugged into a router?

My two PC's are plugged into an ethernet router/modem thingy, both connected with cat5 ethernet cable... I had the same problem saying that the "Cable is unplugged" when everything on the PC was fine - turned out the port on the router was dead... I changed the cable from port 2 to port 3 and it was fine. Now both ports 2 and 1 are dead and I am running on 3 and 4... Time for a new router methinks!