Is the condenser clean and clear? Is the fan running? Sometimes when the fan fails the compressor runs and runs and runs. First thing you need to do is go to the supermarket and pick up a red stick thermometer and find out what kind of temperature you have. Try setting the temperature warmer. Is the coil iced up at one end? If it is there is a good chance the system has a leak and needs a look at from a tech with some tools. Hope this helps good luck.