Replace one XP in XP-XP-Windows7 multiboot

So I end up with XP-Windows7-Windows7. I want to keep the oldest XP install and replace the newer one with a second Windows7. The partitions are all ok for this. I've tried this once before and couldn't get the first Windows7 system recognized by bootmanager. After I format the XP partition and install the second Windows7 system there, what's the best way to get EasyBCD or BCDedit to add the first Windows7 system back into the bootmanager?

Use the Win7 installer to format the XP partition. It should correctly configure the multi-boot if installed last.

If not use EasyBCD 2.0 to Add the missing OS on Add/Remove tab.

Any probs, post back a screenshot of your full Disk Mgmt drive map and Easy listings, using Snipping Tool in start menu, attach file using paper clip in reply box.

Edit - Jon's idea above to try running startup Repair on Win7 if one fails to show up on menu is interesting. Try that first to see if it works and let us know as it may be a shortcut.

I formatted the unwanted XP partition with the Windows7 install disk and installed Windows7 there successfully, but it did not sort out the boot manager and was the only system available at startup. Then booted the DVD again and selected Repair - It automatically brought up a "System Recovery Options" box with the message: "Windows found problems with your computer's startup options..." and I clicked the "Repair and restart" button. That set up my previous Windows7 system which was available in the startup menu as "Windows 7 (recovered)", but the XP system was not available.

I used EasyBCD to add the XP system and then change the target drive, going through each option in turn, and XP would not boot. I sort of expected that, from past experience of the illogic of drive letters and boot file allocations in XP-Windows7 multiboot, so I just copied the boot.ini, ntldr, and ntdetect files from the XP system into all the other partitions, and then it booted.

Then I was curious to understand where Windows wanted the boot.ini file to go. It turns out to be the most recent Windows7 installation, so I deleted the XP boot.ini, etc. files from everywhere else and it's fine. I still don't understand the logic of this - is it because the active Windows7 bootmgr file is there? There are also bootmgr, Boot.BAK, BOOTSECT.BAK, and grldr files in the XP partition - why the duplication? I would delete the surplus Windows7 boot files (if they really are surplus), but am reluctant to trash the setup I have now, unless someone can explain what's going on!

If you used EasyBCD 2.0 as suggested it should have offered to install the XP boot files and then autocompleted the Add.

You're right, gregrocker - I used EasyBCD1.7.2. Last time I tried 2.0 it was build 63 and gave problems, but I'll try build 80 next time.