I suppose it's possible since a FAT32 to NTFS conversion can be easilly done at msdos prompt. Try using your windows Help and Support and search for < convert fat32 to ntfs > to find out the relevant commands.
short of using software like partition magic, there's no way to convert NTFS back to FAT32. i encountered the same problem some mths ago when i was trying to reformat an old notebook hdd (NTFS) for my compactdrive (FAT32).
My recommendation is to leave it as NTFS and read off the data instead of converting it back into FAT32. If you have problems accessing an NTFS partition, do a search on the Internet for an NTFS driver - there are versions for Win98 and Linux. Without saying, WinNT, Win2K and WinXP can read/write NTFS partitions natively.
Do let us know why you want to convert NTFS -> FAT32 and we may be able to offer more solutions.