I recently bought a used Frigidaire Freezer. I brought it home and cleaned it up on the inside. When I plugged it in it ran fine and began to cool down. In a few hours it stopped running. I unplugged it and let it sit for a long while. When I plugged in back in it still did not start. I can hear a very low hum in the compressor area but you have to listed close to hear the hum. Can you give me some advice as to what the problem may be.

Unit probably low on refrigerant and the compressor got too hot and shut down.