Mike is right. The files are still there. Your .inf file is corrupted and couldn't be recovered with the backup file because subsequent saves were used which overwrote the inf and bak files. When this problem first occurs, you need to use the backup file before any file saving takes place.

If you do have another SD card with almost identical content, you can copy it's .inf file to the KN7000 folder of the bad SD card and recover a lot of the file names.