Cable no signal in living room?

It sure sounds like the cable jack in the living room isn't properly hooked up. You will have to try and trace the cable back and see if you can locate where the problem lies. It could be as simple as the line being disconnected from a cable splitter. Of course it could also be due to a fastener being driven into the wall where the cable ran and broke the cable. There is no way to tell without tracing the cable out.