baj300688

HI i'm a newbie to this. I have just recently took some photos with one of my memory cards on my Olympus Digital 500 using two differnet memory cards. Everything went well with the caera and i can view the pictures on the camera during preview mode. Though a probelm has occureed when i have come to placing the picture onto my computer i have found that xp didnt recognise the card in the computer. I am using a external USB card reader which is called Dazzle. SO at first i thgouth it might of been a driver fault and treid the other memory card and that worked correctly. It is just this memory card which windows XP wont recognise though my camera will. The only other option which I could think of would be to buy a USB A/V Out cabel to put my camera direct to my computer. Do i ahve any other options apart from formatting the card?
Thanks in advanced for any help and advice Ben