There is no way to convert the NTFS partition back to FAT32 w/o losing all of your data. If you converted it, my advice to you would be to leave it.
Abra_Volta had a good point, and you sounded terribly rude to him. What do you have against NTFS? It's a far superior filesystem to FAT32 at any rate. Faster, and less fragmentation than FAT32