I would try a new screwdriver from a different company and look for a professional set. If that doesn't work and your screen is bad you can pry it open, it will destroy the screen but you should be able to get the screws out. I have run into screws being rounded out and tried torque head bits. And after it was partially out I had to use vise grips on the head of the screws. But I did have to destroy a couple of screens to get it open. No matter what you need to replace the screws with new ones.