Sliding window fixed plane blocked by screws

I'm trying to remove the innermost panes of my sliding windows so I can apply a heat barrier window film to the panes that are most on the outside. That is the manufacturer recommendations if I read it properly. I can remove the sliding pane easily--just up and out. The fixed pane is, of course, fixed. I then discovered how they decided to secure it in place. There are screws coming in from the top in bottom that anchor the frame. From what I can tell, they screwed it in long ago when the drywall hadn't even been installed yet, and just ran it through everything. Most specifically, I see a screw, tip facing out, on both the bottom and top-- against the fixed pane.
How am I supposed to get that out and replaced when I reinstall the pane?
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