Recovering existing OSs (7+XP+OSX)


Hi, I'm new on this forum and I'm searching for help.

I had XP(x86)+7(64) dual boot on two sepparate hard disks, and also had a 3rd HDD with OSX (Ideneb I think it was) which I used separately, just unplugging the Windows HDDs.
The problem started once I connected the drive with OSX and needed to get some files from the other two disks and forgot to unplug that OSX HDD. Then my wife started normally and tried to log in to 7 and gave an error (couldn't find winloader.exe), so she booted onto XP, which booted correctly.

The situation now is that Windows7 won't start loading and the OSX HDD can't be seen from anywhere, so I unplugged the OSX HDD and left the other two plugged. Only XP can boot. I installed EasyBCD 2.0 and noticed now it can handle OSX too.

I'm not sure if my OSX is still running, I'll test it tonight, but I'd like to have the 3 HDDs plugged and EasyBCD letting me choose from the 3 OSs each time the system boots.

So here are my questions:
- What should I do in order to resurrect Win7? Just that "write mbr" option in EasyBCD?
- If I come to have the 3 OSs working (both Windows with Microsoft loader), which are the steps I should follow to integrate the 3 of them into just one boot menu? (for dummies, i.e. first connect all of your HDDs, boot into 7, add manually each entry, etc)., or should I take other way?
- If just XP is working and the other 2 aren't, which would be the best to do? I mean install first W7, after that OSX, all of the disks plugged, or should I unplug them and work them separately, etc.

I will really appreciate your guidance.

My hardware:
Pentium Dual Core 2.7 GHz, motherboard Intel DG41RQ, 1 GB+2GB Kingston (3 GB) RAM, PCI-E NVIDIA GeForce 8400GS 512 MB from Asus, 3 x Seagate SATA 500 GB + 1 Seagate SATA 1 TB (for data only, NTFS)
1) Yes
2) Write 7 MBR with EasyBCD, use it to add a new XP entry and a new OS X entry.
3) Let's take it a step at a time.

Good luck, and welcome to NST.
I tried the "write MBR" and didn't do anything. It just won't boot to 7, but to XP no problem.

Question: To add the OSX option with EBCD do I have to get it plugged in first? I mean the disk has to be running in order to be able to add it? I guess so, but I don't want to screw things up, OSX is working perfectly now if I unplug the other HDDs.
I don't remember if I did.
I'll try that in that order. I'll let you know.
BTW, would the CMOS boot order matter here? Both disks are identycal, and I'm not sure which one of them is booting now, no matter which one of them I put first, 7 won't boot and XP will.
Yes, you'll need the W7 HDD before the XP HDD in the BIOS boot sequence.
If your BIOS won't let you change the order (some OEMs seem to prevent user choice), then swap the HDD cables. (if they're both SATA, or both IDE)