there are some 3rd party software (dont remember the names, just do a google) that will revert to FAT32 from NTFS. Don't know how well it will work, as I would see a serious problem with corruption. I would just convert the FAT32 to NTFS and be done with it. Just type this in the command prompt:
convert D: /FS:NTFS <enter>
that will convert. backup before doing this just in case. also, of course the D: is what ever drive to convert.
also, you shouldn't need to format.