if all else fails, such as breaking off your bits in a driver, you can walk the bolts out with a center punch, usually if you smack the head of the screws( not in the philips indention) it will free them up and you can twist them out, if not you can walk them around by angleing the punch a little so your driving down on the left side of the head and keep working it around until it is free enough to turn with a screwdriver.