I have an Acer CR-6530 Digital Camera with a 64MB Secure Digital Card that works OK. I have purchased a 1GB SanDisk Card and inserted it, I get the message 'THIS CARD CANNOT BE USED'. I go to Set-up and format the card in the camera, I get the message 'CARD ERROR'. I switch off the camera, and start it it set-up mode, go to Format, execute and then get the message 'processing image' and then OK. i them move to Auto and am able to take pictures OK, which can be shown on the camera and through a card reader on my PC. If I switch the camera off (or it switches off automatically) When I switch it back on I get the same error message 'THIS CARD CAN NOT BE USED', and I have to start over again and lose the pictures that are still on the card. Any body help with this one?