I have a Coolpix S550 - and a memory disk: PNY Optima SD HC 4GB..Have taken vacation photos which show on the camera but does not come up when I put it into my H drive on my computer. It says that I have an optima erra
What card reader are you using? And what is the error message? Since you can view them on the camera, the card is probably fine (unless they're stored on the small internal memory, assuming your camera has that).
Can you connect your camera via USB with the card inserted in the camera to read the pictures? Can you try out the card on a in-store Kiosk? Or buy a new card reader... they're less than $20 usually