Copy the boot.ini (on the "c: - Master drive) to the root of the "e" drive; open it via Notepad/Wordpad and change the entry that reads:
rdisk(1) to read rdisk(0)
in both the lines that refer to XP.
Also copy over the ntldr/ntdetect.com to the root of the "e" drive.
Then set it as Master (no Slave?); afterwhich boot with the XP CD and run the fixmbr routine.
Do not re-install/repair (as in replace or whatever...) the current instalation it will find. All you are after is the fixmbr routine.
All things being equal the "e" drive will now boot...; and XP installed there (when it was in a Slave posn.) will still boot as though it was drive "e"...; all the current path statments will remain.
And at any time you can reset the drive as Slave to the curent Master and it will still boot as now - providing you do NOT remove the XP boot/start-up files on the current Master, nor wipe the mbr on that current Master...