Might have been a mistake to drill out the screws. The screws go into a 5/16 " square rod that fits tightly into each half of the windshield frame. The frame and these rods are rusted together. Soak in ATF and acetone 50 - 50 mixture for several days. after soaking apply heat and use a 1 X 4 block of wood to cushion the blows of a 3 # hammer against the frame halves. It takes a lot of soaking, Heating and whacking to get the rust to break free and the two halves to start moving. Lots of luck!