switch on the wall near the switch for the disposal....that switch may have been accidentally turned off.
or verify the circuit breaker/fuse for the dishwasher is not tripped or blown,,,if it is reset or replace fuse---Sounds like you have already eliminated this as a cause!!
if all the above is not the cause, remove fuse for the dishwasher to safe power to it,,,then remove the kickpanel at the bottom of the dishwasher and access the wiring junction box usually located near the front of the bottom of the dishwasher....remove the cover panel if one exist and verify wire nuts and wire are securely twisted together. then reinstall fuse and retry turning on the dishwasher.....if you have a volt meter ....safely put it across the power wires to verify power is to the dishwasher. if all this fails to isolate a loss of power to your dishwasher then call an appliance repair service..good luck. LJ