Crying is what you do when you're a little unhappy, somewhat upset, very happy, have something in your eye, or something like that.
Weeping is what you do when life has just hit you with a major WHAM and you don't know how to handle it. On very rare occasions, when you're really happy and perhaps extremely relieved, you might also weep.
I've cried plenty of times in my life, but I don't think I've wept on more than a handful of occasions.
Paul
