"Isn´t she happy? Is not she happy? Why not is she happy? Why isn´t she happy? " You wouldn't ever use "Why not is she happy?" If you did use this, it would be, "Why is she not happy?" However, contractions are used the most often (in American English, at least). You wouldn't really use the more formal "Is she not happy?" that often.

1. Isn't she happy? Is she not happy? 2. Why isn't she happy? Why is she not happy? a) I believe that the kind with contractions is more usual. b) The kind without contractions is more formal. c) The kind without contractions SOMETIMES means that the speaker is angry or surprised: Teacher: May I have your homework? Mona: I did not do my work. Teacher: What! Did I not tell you to do your homework? ***** Alice: I hear that Mona is unhappy. Claudia: How can that be? Is she not married to a very rich man who gives her everything she wants?