Switch off power so the clock goes out.
Switch on power and depress two buttons at same time 2nd & 3rd from left. Whilst these two depressed adjust plus and minus to set the time (any time will do). Clock should now be reset and ovens should work...
This on my STOVES cooker but I bet all the manufacturers buy the same digital clock assembly - try it if you have a five button timer/clock.
Bucko
October 2008