You can try to change the vertical and horizontal to make it less horribly zoomed in, but I doubt that’ll actually do much. I suspect, for no reason at all, that the electron gun is too weak. It’s emitted electrons are less energetic than they should be, and so their trajectories are bent more by the magnetic fields and they don’t excite the phosphor as much. Also, the phosphor has probably been burned away from abuse.

It doesn’t really matter, since there’s nothing you can do to fix it at this point anyway.

Are you running a computer recycling center or something?