While you were testing the red switch at the bottom of the unit, you may have noticed a small opening in the center. If the unit is clogged or humming, you can try to free up the unit by using the wrenchette (Hex-Torx key) that came with your unit or a 1/4 inch allen wrench. Simply place the wrench into the center hole and move it back and forth until the whatever is clogging your unit is dislodged. Once your unit is moving freely, turn it back on to test. If the unit still won't turn on, it may be necessary to take the unit apart.
Another common cause for a leaking garbage disposal is the disposal flange. A leak at the very most upper area of the garbage disposal could be the garbage disposal flange which goes through the sink. A garbage disposal flange should be sealed with Plumber’s putty and then tightened from underneath the sink. If this is not tight enough or if it has managed to come loose (which can happen) then the garbage disposal will have to be taken down so the flange can be resealed and then the garbage disposal can be rehung.