Lots of options to recover the boot sector. Also look at using Knoppix (see Robert P (Moderator) threads). Go to FAQ and do a search on Knoppix. It will allow you to have a bootable O/S on CD that you can use to access your drive and if you have both functional you can copy your files over to the slave before rebuilding the master if needed.
I am running Win XP Professional w/ all current updates and service packs on my master hdd. I defraged my secondary slave hdd and ended up corupting my master boot record on the secondary drive. It now shows up as an unformatted drive. How do I recover from this without losing my data on the drive?

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