failure : Sandisk 64GB Extreme Pro SDSDXPA-064G SDXC Card

Hi. For the last few days when ever I inserted my card on to the reader it would say 'windows needs to format the disc". And then it would say eindows was unable to format (win 7 64)

With the card in my camera it was able to read it . Then I formatted the card on my pc. Now the card can not be read in my canon 6D. Help