Keypad Problem?

Upon plugging in the microwave, you get flashing zeros on the clock/timer display. You can initially input an amount of time after pressing the cook button. Upon pressing the start button you get no light, no microwave sound, and no timer countdown. If you decide to set the clock after plugging in the microwave, you will get 'Err' displayed on the clock/timer. I thank you in advance for your attention in this matter.