Outside A/C unit won't kick on

Hey guys, my outside unit(heat pump?) will not turn on, the inside temp is at 82, I set it for 76 but nothing happens, I walked outside after reseting the therm. again to 76 and i hear a sound from the unit like it is going to turn on but it just quits, is it possible that the fan in the unit has seized up? i tried using the heat and I feel hot air coming from the vents. any ideas guys