Game wont run, Don't know why

My game randomly stopped opening when I press the play button for no discernible reason. Does anyone know why this would be?

I am on the current GameMaker version and game_end() appears nowhere in the game

I have:
- undone every change I did between now and when it last worked properly
- Turned GameMaker and my whole computer off and on again

I haven't:
- touched any of the files for the game
- moved GameMaker, the game or any files to a different location
- touched any settings

When I...

Game wont run, Don't know why