If the disposer is making a humming noise, that means it's jammed. Unplug the disposer and inspect inside again to make sure there are no foreign objects. You can then release the disposer and plug it back in.
How to release a garbage disposer:
There is a small hole on the bottom of the disposer, right in the center and near the red button you were talking about. Insert a 1/4 inch Allen (hex) wrench (typically supplied with the disposer, can be purchased from most hardware stores) in the hole and move it back and forth until it moves freely. Plug the disposer back in and try it with the water running (you should not use a disposer without water running through it).
Hope this helps.