Copy your files to a local folder on your hard drive, format the card and copy the files back?
-> BUT files are never "formatted." The drive they are could be formatted but never a file.
If the card has some file system error, the easy fix is to copy the files off the card, format the card then copy the files back.
I found an old SD card that my laptop's operating system can't open because it says that it is a read only file. It will reformat it but it says it will erase all data from the card when it does. I'm not sure what's on it and do not want to delete anything until I know what it is. How can I open it? I'm using Windows 8.