Thanks Kong for this interesting experiment. In an increasingly wired society, we clearly forget that everywhere around us there are fields of magnetism. I use laptops regularly - but fortunately they spend most of their time in docking stations at home or office. But unconciously I take off my watches anyway to stop them from scratching on the surface of the notebooks anyway. Thank goodness.
This makes me think about all the different things we do that exposes us. Like my wife using her hairdryer?
BTW - the distance of the compass from the top of the wrist to the surface of the keybard on the PC is further than the motor of a small watch winder from the watch. May be you could try out the compass experiment on a watch winder?