I have Windows 7 on SSD 1.
I have Vista on SSD2.
I have UEFI set with the EFI partition on SSD 1.
All is working fine.

I had an older SSD from a now defunct computer so I put it in and installed windows 8.1 on it - I don't really like 8 or 8.1 but want to have it available to obtain a free licence for windows 10 as Microsoft say they will do.

After Windows 8.1 is installed and I turn off Fast Boot Windows 7 works as normal - and obviously windows 8.1.

But Vista Blue Screens with a STOP error!

So I try the repair option using the 8.1 Install media but it fails - Vista still blue screens.

I booted 7 and checked using EasyBCD and found that 7 and 8.1 correctly referenced their respective winload.efi file but for some reason the repair process changed the Vista entry to reference winload.exe ??

I tried several other options but to no avail.

I then deleted all OS entries using EasyBCD and tried repair using 8.1 install media.

It recovered all the OSs and 7 and 8.1 boot fine but Vista blue screens and - you guessed it - it is set to load winload.exe, not winload.efi - hence the blue screen stop error.

I again deleted all OS entries using EasyBCD and tried repair using the Vista install media.

It recovered all the OSs and 7 and Vista boot fine but 8.1 reports a file mismatch error - obviously - and it refuses to boot !

I have no doubt if I use 8 Install media it will change the Vista entry to reference winload.exe and cause the blue screen again.

Can anyone tell me if this can be fixed or am I forced to choose either Vista or 8.1 ?