In this case, it sounds like the card is bad. All you can do is try to clean the gold fingers with a soft cloth and alcohol, and hope that works. It may have corrupted data on it, and be unusable. The best way to know is to buy another one ($9 at Walmart), and then you will at least verify that your phone and computer are good, and the old card bad. Hope it's just dirty fingers, good luck.
Answers & Comments
In this case, it sounds like the card is bad. All you can do is try to clean the gold fingers with a soft cloth and alcohol, and hope that works. It may have corrupted data on it, and be unusable. The best way to know is to buy another one ($9 at Walmart), and then you will at least verify that your phone and computer are good, and the old card bad. Hope it's just dirty fingers, good luck.