If the air conditioner has a drainage spout, which may or may not be present, be sure the spout is clear from clogs and is allowing the excess moisture to drip out of the unit. Usually the hose can be easily cleaned from the outside with a stiff wire and a piece of cloth.
A humming sound from the air conditioner unit with no air seeming to come from the unit is a good indication that the fan has seized or is no longer working. Replacing the fan is relatively simple if you have a basic understanding of how the unit works, but if you are unsure contact a technician.