The screw farthest from the optical drive would not come out, all other screws came out fine with my screw driver and the screw looks ok, any tips on how to get the screw out?

On step 10 the last screw, the one farthest away from the optical drive, would not come out. My screw driver is fine and the screw look ok but it will not come out. I'v been trying for 30 minutes now.