Hi, demo mode should cease if you unplug the unit for say 60 seconds and then plug in and set the clock and carry on, if this does not work, A/ read the book, or in a final last desperate bid call me with the model number and I will look it up, or you could contact the demo kitchen at panasonic in bracknell, details on the web.
kindest regards
B.E.S. Microwaves
01424 447799
patrick
March 2009