I have had an HP 315 for a few years & have only been using the the 8MB compact flash that came with it. I recently purchased a SD ultra II 1.0 GB card & used it on a trip. I took several pictures with it. Took the card to walmart to print the pics (which worked great), put the card back in the camera & now it will not take any pictures. I just get 000 flashing on the photo counter. I have tried formatting the card again, it says it is formatting but I still am not able to take pictures. Any ideas of what I can do or what the problem is? Thanks alot!