Need more info. Is your problem limited to DC (lights and other stuff operating off of batteries) or does it include microwave and other stuff that operates off of AC?
Assuming the problem is DC only and the lights etc only work when your connected to shore power there are two likely problems 1) dead coach battery or 2) defective auto reset circuit breaker or battery fuse (usually located near battery). Depending on how your rig is wires I suppose it's also possible that your battery disconnect switch needs toggling or needs replacing.