DESPERATE!!! Looking a name of a movie with Bruce Willis?

A year ago I saw a movie (half of the movie from the end) with Bruce Willis, where he had very light blond hair, very tense and fantastic scary movie. He was shooting everyone, and i think he was a psycho in the movie. Please everyone, do you know which movie I am talking about? I want to buy it! Last night I was excited it was that movie, but it was very different one. In this movie I remember in the end he killsed a silly looking kid that had a big scary shooting gun. He was like a psychopath... HELP!!!!