The card itself can most likely be saved by reformatting it in the device. This will cause the loss of all data on the card, but you should be able to re-use the card with no problem. If you need to recover the data, do not reformat it. If the data is irreplaceable, you may want to use a professional data recovery service to attempt to retrieve the information. If you want to try recovering it yourself, put the card into a card reader attached to a computer running Windows and try running "Scandisk". If "scandisk" asks to fix the file system on the card, let it. This may allow you to read the disk. If so, immediately copy the files you want to save to different media, or your hard drive. Once done, the card should be reformatted before being used again.