Whaaaat?

I have had a problem with my new camera. When I was taking photographs earlier on today my memory card crashed. My son Graham had said that the memory card that I used from my point and shoot camera was not fast enough so he went out and bought a new one for me tonight. Still having a problem with the display saying that there is no memory card.
However Graham managed to format the card: but ,of course,it was too dark to blip outside - so back to Mac! He always has that expectant look with his head to the side.