Dishwasher will not run through cycles

When I start the dishwasher it drains water and then fills back up. After the dishwasher fills up with water it stops. The knob on the front continues to go around and eventually gets to the drying stage where it start to smell like burnt plastic. I can hear a faint humming sound when I am looking under the dishwasher. I have checked the hoses and could not find any blockages.