It sounds as if the card got damaged. GParted should at least show the partition(s) on the card and, if it's a FAT or NTFS partition, Windows should format it (right-click the card and choose Format). (If it's a SanDisk card, go to
SanDisk microSD Tech Support, upper right, Live Chat, and they'll replace it. If it's someone else's card, and it's still under warranty, and you can convince them, they might also replace it. (SanDisk costs a little more, but having to deal with them once makes it worth the price. No nonsense, if it's under warranty [the shortest warranty is 5 years for the cheap cards] and not physically broken, they'll replace it.)
