My first suggestion would be to make sure the memory card works in a card reader; it may be corrupted. Secondly, try to get hold of another card and see if the problem is the same.
Do make sure the other card is a genuine branded product; ideally ask at the shop where you bought it if you can try a different card in there. There are a lot of fake cards around, mostly from online retailers, which produce this kind of problem.
If the problem persists even with a new card, it could be an internal fault with the camera. Let me know and I'll try to help from there.