Hi Tine, sounds like a Panasonic to me, the answer is in the user guide but well hidden deep into the booklet. find it under child lock, memory this time of day is not too good but if it serves it involves holding down the start (maybe stop) button for 5 seconds or so, any problems my contact details are on microwave-repairs.co.uk
kindest regards
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Try fixfault.com to fix microwaves.