My macbook pro was working fine until i tried to view some pictures from my camera sd card. The macbook didn't recognize the sd card when i inserted it. I removed the card and then clicked on iphotos. The computer then locked up and the only way i could do anything was to power it off holding the power button down. After it restarted, i clicked on iphoto and the computer locked up again. Any idea of what is wrong and how i can fix this? Thanks!