No Power to outlet
This kind of detective work can be really hard for a homeowner. It might be solved by pulling all the nearby oulets and looking at the connections to see if a mistake was made or if something is obviously broken. It might require tearing out drywall to get to the wires underneath and figuring out where a wire was cut. You may get lucky and find an obvious problem, or it could be some hard-to-identify problem that you'd have to nearly destroy the room in order to find.
If nothing is obvious to you, it's probably a good idea to get some professional help. They see this sort of thing all the time, and might be able to identify and correct a problem in minutes that you would have worked days to discover and correct.