This will take a vise, OR another set of hands, and it seldom fails. Insert the proper size torx wrench, apply pressure COUNTER-CLOCK WISE, and at the "same time" TAP Hard on the top of the wrench with a small hammer. This will in effect cause the threads to loose contact with one another for an instant, and allow the screw to turn. Usually after several small increments of movement, the screw will then screw out. HEAT WITH A TORCH is an iffy thing as if SLIGHTLY over done the temper in the screw could be compromised and cause it to break off in the hole, and then you have a different and usually more difficult problem.
