First of all you need to read this -->
Bootloader configuration in dual boot environment .
Though its not the solution of your problem but you surely get some idea that where you are actually making mistake.
Secondly... You don't need to have third party bootloader at all. Fedora's bootloader "grub" can do everything easily. Also there is nothing to do with second HDD's boot sector. The only one which is in action is Primary HDD's boot info.
So if you have messed up everything already then simplest way is that you first install winXP on primary with default options and then install Fedora on other HDD but choose to install MBR on Primary HDD .
This way you will get Grub as main bootloader which then will give you choice to boot to linux or to winXP, on choosing winXP you will be then presented with winXP bootloader if you have any other windows installed also. But I think this way you will get what you want.
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