Cancel Button Problem in Microsoft Word 2007

I am using Microsoft Word 2007. Everything is OK but when I click the close button, it says “Do you “want to save changes to …” And Yes, No or Cancel it's normal , that’s not the problem.
But when I click cancel it should do anything, but in my case this dialog box repeatedly asks the same question even if I press the cancel button.
What is the problem I cant understand? And what’s the solution?
