My Kenmore elite HE4 electric dryer will not work. The screen displays "PF" power failure, but there was no power failure. Th dryer is maybe 2 years old and worked fine until now. I tried holding down the START button but it still doesn't work. I tried unplugging and tripping the breaker still nothing. The end cycle light beeps constantly and unless I hold down a button it keeps beeping. What can I do to fix this?