SeaTools will not work with external drives, AFAIK.
Was the DVD player accessing the video files in the FAT32 partition or NTFS?
If I were approaching this problem, I would first investigate the extent of the damage with a disc editor in readonly mode. For example, you could use DMDE to search for backup copies of your original boot sector(s). Select Tools -> Search For Special Sectors.
DMDE (DM Disk Editor and Data Recovery): http://softdm.com/download.html
I could help you with this.