|Unfortunately memory cards do go bad over time. There are programs out there that can sometimes recover the data on the cards but it's it or miss. DO NOT format the card, you will run a greater risk of the data not being recoverable. Do a Google search for memory card recovery programs and you will find lots of programs that can help you out, many are free.|
If/when you do recover the data, throw the card away after that, it's lifespan has ended. You may be able to use it again for a while but why run the risk.