|If you can't play DVDs now, that probably has nothing to do with why you can't play them. |
The Windows operating system itself does not come with a built in DVD player that can play encoded DVDs, such as movies.
At least one third party program must be installed in Windows that can play encoded DVDs.
E.g. Cyberlink's Power DVD.
If your computer is a brand name system, it's original software installation may or may not have come with a third party program that can play encoded DVDs.
If Vista was installed from a regular Microsoft DVD, or if you re-installed Vista from an operating system re-installation DVD that came with your brand name computer, the operating system does not come with a built in DVD player that can play encoded DVDs.
If you DO have a third party program installed that can play encoded DVDs, but you can't save them as a recording on a FAT32 partition, or you can't stream them to a FAT 32 partition, that's a different matter.
A small number of programs are optimized to make recordings on NTFS partitions, or to stream to NTFS partitions, but I don't know of any that will not work on a FAT32 partition too.
E.g. Media Center in XP MCE, and probably Media Center in Vista and Windows 7 versions that have Media Center, will "complain" if the location where recordings or streaming is saved on is on a FAT32 partition. The recordings still play, the streaming still works, but not as well as it does on a NTFS partition.