i)
install on DOS/WINDOWS/LINUX (basically on foundations or situations , especially on OP systems)
install in Computers/vehicles/TV's/rooms/garages (in a place)
ii)
full spelling A: You are a cute girl.
full spelling B: You are the cute girl.
abbr. spelling A: (face to XX) A cute girl.
[a] cannot be ignored otherwise it makes nonsense whether the full expressing A/B is.
========================================================
IS that clear enough? (ll14)