Pretty self-explanatory, if you happen to be a computer master like me then this sorta thing is bound to happen.
It's a common problem and rather easy to fix.
1) Check that the SD card hasn't fallen right into the depths of the CD drive.
- Get a paper-clip and bend it into an 'L' shape. It should 'hook' neatly onto an SD card.
- Insert carefully towards the upper half of the SD card and bring down towards the bottom of the CD slot.
- If the SD card is here you will feel it - in which case just give it a tug and it should come out with the paper-clip grabber
2) If you cannot feel the SD card, then it has most likely fallen out of reach.
- At this point, turn the mac off and unplug it from the wall.
- As unorthodox as it sounds, pick up the computer and turn on it's side, with the SD/CD slots facing towards the ground.
- Carefully, give it a light shake, and hopefully gravity should work it's magic so the SD card will be in reach of our 'grabber'
- Use the grabber to retrieve it.
Congratz' u are a winrar