My unit has power, but it won't turn on at all.
This means that something is seriously wrong with the unit(blown amp, shorts, opens, etc.) however, you can reset the unit by unplugging the unit, holding the A and B channel buttons on the face of the unit and plugging in the reciever. the display should flash at 1 second intervals. if it doesn't stop flashing on its own then unplug and replug and you should be good to go! good luck.