If your talking window beltline at the bottom of the window... You could try to spray them from inside the door with Kroil and see if they losen. If they are too far gone, drill with a bit slightly larger than the shaft if the screw. The head will spin off when the bit reaches the level of the trim. If not, switch to a slightly larger bit and that should shear the head. Once you have the trim off, grind the area flat, reinstall trim, marke holes, remove trim and drill new holes. It can take time, I had some issues in that department too!
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