LinuxQuestions.org - How I screwed my mbr...FC2 & W2k, windows unable to boot even after reinstallation!

My project was to install linux (FC2 in this case) and windows on two separate drives (let's call them A and B) and simply switch the two hard drives with removable bays to avoid messing with boot loaders and keeping the two OS completely separated. So I had W2k on the slave drive (B) and I installed FC2 on the master (A), but even if FC2 ran perfectly, I was unable to boot W2k. Actually I found out that booting is not as simple as I expected because when I swapped the drives I ended up with the same GRUB screen...Furthermore, I discovered that my entire W2k hard drive (B) have been screwed up by FC!!! Now it's just "unformatted space"!!! Beats me how I managed to do this, but now I'm trying to delete FC2, reinstall W2k (or XP, doesn't matter) on the "B" hd, find a nice rescue utility and try to save as much data as I can from the screwed hard drive (A - that I obviously didn't touch to prevent overwritings...).
Too bad it seems I can't even go back to Windows! Even if I booted from the cd and fixed the mbr and reinstalled Win (a couple of times, actually...), I still get a "error loading the operative system" and a stuck screen when I try to finally boot it from the HD...

I'm trying not to get angry with Linux since it's probably something that happened because of my lack of experience on that OS, but I do need help now! I still don't want to mess up with GRUB or LILO (I read many postings about partitioning problems), but it looks like my method didn't really help...and I also read about those switches (Nicklock) and people happy with them...shouldn't it work then?

Sorry for the verbose posting and thank you in advance for your help!