After a power failure most digital clocks have the zero's and auto flashing. These ovens will not work if clock(time of day) is not set. By pressing incorrect buttons, you can complicate things further. Recommend turning off power to oven for a few seconds, then follow manual for resetting clock, which is usually holding down the 2 buttons on the left hand side simultaneously, and holding down these two press the + or - key to advance clock.