Backup your datas and try "NTFS to FAT32 Converter" with the "Convert NTFS to FAT32 without Losing Data" option. The Free Edition is "Limited functionality" to 8 Go. (NTFS to FAT32 Free Edition can work on Windows 7/Vista/XP/2000/2003/2008, but it only supports converting the NTFS partition maximum 8GB to FAT32. The paid editions can convert NTFS that is larger than 8GB to FAT32. Also, you can use the Free Edition to convert any FAT, FAT32 partition to NTFS and no limitation)
http://www.aomeitech.com/n2f/convert-ntfs-to-fat32.html