i got my dm500c with a ntl digital smart card with nagravision printed on the back. when i remove the card the channels would go blank and inserting it again gave me back the channels. the box was flashed and now the card no longer work. the previous setup on the box when the card was working was pli-helenite image. i reflashed with that image again and still nothing working. what do i need to get this card to work again. iam still learning ........... just give me some tips or ideas please.