DIAGNOSIS Lost power. This is almost always a tripped GFCI outlet, a tripped circuit breaker, or a loose/disconnected power cord.
FIX Check the kitchen GFCI outlet (the one with the reset button) that the dishwasher is plugged into. Press the RESET button. Then, go to your home's main circuit breaker panel and ensure the 15-20 amp breaker for the kitchen appliance circuit is fully in the ON position.
IF THAT DIDN'T WORK Pull the dishwasher out from under the counter (carefully) and check where the power cord connects to the unit at the lower front access panel. Ensure it's plugged in securely. Also verify the other end is firmly in the wall outlet.
HEADS UP If power is confirmed at the outlet and connections are tight, the main control board is likely dead. This is a major repair. Don't keep flipping breakers on and off; call an appliance technician.