Re: 57 TR3 Still fighting window frame holder oner
It seems to me, if I remember your earlier post, that you are talking about the two chrome Dzus fittings at the bottom of each of the two stanchions, which secure the windshield to the body of a ('57?) TR3. If so, these are not screws, but Dzus fasteners. You are trying to turn each about a quarter turn counter-clockwise.
You should be able to get at the back side of all four with PB Blaster, etc., from inside the car. (You'll have to pull any carpeting away from either side).
Those Dzus fasteners engage a spring, and it's probably that spring which has become the center of a solid rust cake. TR3driver's suggestion about using a dremel to get some purchase with a driver sounds best to me. I would personally be very cautious using a hammer and some torsion device. You could make a terrible mess of the body.