I use EASEUS Partition Master to do all of my windows partitioning as i find it a simple and easy to follow GUI.
select the drive you want to format - click resize - make the existing drive small enough to hold whatever you want in Fat32 and change the format type as they are usually NTFS.
Make a new partition with the now largly unused portion and make it primary and unformatted.
Apply that and wait until it finishes and then use something like WBFS manager 3.0 to format the unformatted partition.
*** Be very careful playing and make sure your selecting the correct drive letter every time !! ***