Corrupt Memory Card Unformatted Recovery

"My memory card is corrupted because it says memory card is not formatted when I use my digital camera to take pictures. The memory card has been used for several years for my digital camera. I tried to insert the memory card to another camera and also connected it to my computer, I still received the similar error message that memory card needs to be formatted before I can use it. Can anybody tell me why my memory card shows such kind of error message? How can I fix the error and get back all files stored on the memory card?"