Finepix A500 "Card not formatted" message?

My Fuji Finepix A500 will not recongise the DX cards, It keeps telling me the cards are not formattted when they worked well for years. I have 2 cards and both are regarded as unformatted. I have tried formatting with no change in the response. The camera was working fine until this happened.
We had to replace it on holiday so I dont want to spend much fixing it.