|The boot sector, assuming you are talking about the Master Boot Record, on a Seagate drive is exactly the same as the boot sector on a WD drive, or any other drive from any other manufacturer and has nothing to do with the format of the drive. The master boot record is put there when the drive is partitioned.|
The volume boot record is different for each file system and is put there during formatting. Strangely enough, it is still identical to a volume boot record on a Seagate drive, a WD drive or any other drive,
Forget about drive manufactures. All drive manufactures follow the same conventions as far as partitioning and formatting. It is the Operating System that is the deciding factor.
If you want the 500GB drive to boot the computer you are going to have to install an Operating System on it. There are ways of repairing a corrupted boot sector, but it needs on operating system on it for it to work. If it is already formatted it will already have both a master boot record and a volume boot record.
So if you tell us exactly what it is you are trying to achieve and maybe someone can help you. Forget about one drive being Seagate and the other WD, it is irrelevant. The information mentioned by Worldlibrary is very relevant.