Windows 7 fails to boot after copying 500GB HDD to 1 TB SSD

I cloned my existing 500 GB HDD to a new SanDisk 1 TB SSD (via CloneZilla).

Now, I'm having trouble to get Windows booting again:

• SSD itself works fine, I can access it via Ubuntu (booted from USB)
• the SSD is NOT recognized by the BIOS if I go into the BIOS setup menu
• I then added a new partition to install Ubuntu as second OS on the disk, this works fine
• The Ubunto Bot Loader (Grub) shows Windows 7 as an Option
• When I Select this option, a flashing _ shows, similar to what is described in Windows 10 fails to boot after HDD clone to SSD
• When I boot from the Windows 7 DVD and select recovery, my Windows gets detected
• However, if I do "bootrec /RebuildBCD" or "bootrec /ScanOS" it does NOT find Windows Installations (!) i.e. it shows "0" installations found
• I tried bootrec /fixMbr and bootrec /fixboot which did not help; also the automatic repair did not help

What is the difference between what bootrec is doing to find an installed windows (which does not work) and what the recovery and GRUB and others do that do find my Windows?

I still try to avoid to do a re-install of windows ...