Audrey, there is no need to Panic !! Just because the little tab is missing, does NOT mean that you cannot READ the card content. The lack of the tab only means that you cannot WRITE to the card !!
You should still be able to use Fred's program, the Panasonic Song Manager, or indeed WIndows to READ the 'faulty' card's content and copy to another card. In fact, you should still be able to read the card in your KN7000......
A simple method would be to insert the card in a USB Reader, connect the Reader to your PC and copy the 'PRIVATE' folder in the card to a temporary location on your PC - for example your Desktop. Then remove the 'faulty' card from your reader, insert a new card and copy the 'PRIVATE' folder to the new card.....