My cat won't stop making noises?

Have you thought of getting one of those sonic repellents that are motion activated? They're commonly used to repel pesky animals that have very sensitive hearing such as mice, rats, raccoons, and skunks. You could try setting one of them up near where you don't want your cat to go and it makes a sound that will hurt his ears if he gets too near it. You won't be able to hear it, of course, because you can't hear as high frequency sounds as a cat can but it will be loud and clear to him.