What happens when an equip spell card loses its target, because it is turned face-down or its destroyed? Is it destroyed or simply "sent" to the graveyard? ...and does this make any difference? 
When a monster equipped with Premature Burial is tirned face-down, what happens to Premature Burial? And to the monster? It doesn't matter if Premature Burial is destroyed or simply "sent" to the graveyard, the monster is now unaffected by this card, right?
When a monster equipped with Premature Burial is tirned face-down, what happens to Premature Burial? And to the monster? It doesn't matter if Premature Burial is destroyed or simply "sent" to the graveyard, the monster is now unaffected by this card, right?