If your memory card is corrupted, the only simplest thing that you can do is reformat it, first connect it to the computer then format your memory card, and then put it into your cellphone and format it again so that it will automatically put your system files, like image, audio, video, others and system folders to your memory, the only sacrifice by retrieving your memory card is loosing your data and files

Have you tried with any other memory card .............if you are not able to recognize the memory card there is chance that the slot where memory card is placed might have damaged so contact the service center to get the problem solved ...............