My cat won't eat her food!?

[Fraser]

I'm Australian and I got my cat a new brand of cat food called Purina Supercoat and the flavour is chicken and liver. Its dry food and she won't eat it that often. We had left out some old food boxes from before we bought her the brand and she hits the boxes around till food comes out. So I can't go back to that food because she can get it out but I don't want to stay with the other food if she won't eat it as often.