it's not the song that was playing when the robot was talking to the girl; it was the one that was playing when it went through the slideshow of nagisa's, tomoya's, and ushio's life together.
it's played in this video after a few minutes:
http://www.youtube.com/watch?v=rDk9dJhYeO0
it's played in this video after a few minutes:
http://www.youtube.com/watch?v=rDk9dJhYeO0