The built-in formatting in Windows will not allow you to format a drive larger than 32GB as FAT32, and the original poster has a 64GB drive.
This is an artificial limit, however, and there are third-party tools available, that will format a 64GB drive as FAT32.
ExFAT and NTFS formatted drives may not be compatible with DVD players, so using FAT32 is the more compatible choice, but this unfortunately requires using a third-party tool for formatting.
Here's one free tool for formatting (large) drives as FAT32:
Formatting your drive will erase all content on that drive, so remember to save anything you need elsewhere before formatting.