Why not recognize any SD memory Card included the one previusly used?

Why not recognize any SD memory Card included the one previusly used?

I have susccessfully used a 2GB Markvision SD card and also a 8GB SDHC card bun after some months without use the camera, it shows in the screen the message: "Memory card error". an d also SD blocked. The same is for any other new or used SD Cards.Obviously It is not possible to format SD card nor restore options