What's this movie's name?

In the movie a girl attacks a guy (don't remember why - they're
teenagers) and he gets knocked unconscious. She thinks he's dead so
she hides his body. He then wakes up in "spiritual form" and finds
that the only person who can see (and save him for that matter) is his
attacker. In the end she helps him and whatnot.... what's this movie
called????

Also: I cannot remember the actors names... :P