My Powershot 620 give's me A no memory card, I have 4 different card's including the original from Canon but none are working. They are all formatted too.
If the camera is still under warranty Id go that route.
You could look in the card slot with a light and magnifying glass for some dirt in there or perhaps a broken contact inside which will mean it has to get serviced...you can clean out any dirt in there with compressed air
