My roommate's room right next to mine has a working ethernet port, and mine does not. It's not a chord problem or computer problem because my computer works with the same ethernet chord in my roommate's room. I have a 2009 MacBook Pro if that helps. Please, what can I do?

I'd contact the network technical support help desk. The cable to the port inside the wall might be broken or inactive.

Hope that helps.

improper installation, maybe someone was hanging a picture and drove a nail through the cable inside the wall? maybe it just got unplugged from the router/switch/etc.