c:\windows on the SSD, but the BCD partition on the HDD ??!

[Ulysse]

Hello !
Suffering punctually but for years because of a very strange Win 7 Pro installation split on my two drives: SDD and HDD.
Today my HDD disconnected (dying?) so my Win7 could not boot again.
The HDD eventually reconnected, but Win7 could not boot, but it did with a Win7 repair DVD. But again my HDD disconnected...

HDD: d:\ for my data, and E:\ 100Mb presumably the partition (?)
SDD (MBR):  c:\windows  Z: I have created 100 Mb to make it replace the E:

I'd like to MOVE the OS part (partition?) from the HDD (E:) to the Z: of my SDD where c:\windows already is. To have all the OS on the SSD only (not half on HDD anymore).

I've just set Z: as Active (C: was Active) and could do bcdboot c:\windows /s z:  
I am now rebooting...if it fails, hasta la vista... :o(

Thank you very much for your help !
Ulysse

PS: I plan to upgrade from Win7 to Win10, but presumably better to solve my SSDvsHDD problem before upgrading.