If it were me, i'd very carefully drill a small home in the screw. Then, i'd use an easy out or something to turn it. If you turn it enough, it shoud come out, stand off and all. The dremel tool is also a good idea. But.....i strongly recommend extreme caution. You can ruin your mbod very easily with either of these ideas. It may also be possbile, if you can access it from the back, to use a drill to get it to turn. By the way......It isn't necessary for these screws to be very tight. All they do is hold the mbod in place. it isn't going anywhere...... Just get them snug. No need to tighten them any more than that. Good luck.