Hey tm5con,
What I would do is set up a cover area (the line used in the actual game to let you know when to press the buttons). Then give all your notes a different variable.
Now just add the conditions that when you check if the answer is correct you also check if the answer is not right.
I hope that made sense - If not I know there is a couple of really good examples of these types of game lingering around the forum so might be worth a good search.