I just nipped upstairs, putting my hall light on, as i got upstairs i put the bathroom sound. where i heard a 'ping' the bathroom bulb had gone. But as it did the hall light went off too, so i check the other lights upstairs like the bedrooms, no power, yet i can still hear the TV down stairs. So i go downstairs and check the electrick box, you know with all the switches, Upstairs lights, down stairs lights, cooker, poer sockets, doorbell etc And the 'Upstairs lights' is in the off position? How did the bulb going, turn the switch to off? What just happened?