Buy a new digital copy
If every step in this list has failed, then your last resort is to just buy the game again. It sucks to pay twice, but a new Steam or GOG copy will almost certainly run properly on newer operating systems.
If every step in this list has failed, then your last resort is to just buy the game again. It sucks to pay twice, but a new Steam or GOG copy will almost certainly run properly on newer operating systems.