Trouble formatting card

Did you happen to write files to one of the cards from the computer, or delete files from the card through the computer before that happened? This problem has been known to happen in such cases. Remember to only *copy* files from the card to the computer using the card reader, and only delete files using the camera. Anyway, try turning off the camera, pulling and re-inserting the card. If it doesn't work - try it a few more times. If it still doesn't work and you've got nothing to lose, try deleting any files you may have written to the card using the computer, and then try again. But the fact that the new card didn't work as well might mean that it won't help. Good luck.