Hardware Need help reformatting SD card.

[BhenBen_85]

Hi I have 64GB memory card on my SKY3DS and decided to remove it and change it with 8 GB and put the 64GB to my New 3DS but when i plug the 64 GB card to my laptop it only show 518kb something, and i open it up on DiskWritter the latest one,and tried reformatting it from there still cannot be reformatted, i tried 2 tools for reformatting its say write protected but its not on write protected. How can I reformat this memory card so i can use it on my 3DS. its shows when i go to disk utility say 59gb , and on DiskWritter the games i installed still there click format nothing happend , I click reformat nothing happend also. please if someone know how to format this please tell, cause i'm switching from retail to digital download.