To boot Windows Vista, 7, 8 from hard disk you need:
- Windows MBR on disk
- Windows NT6 PBR (partition boot record) on active partition
- \Boot\BCD (boot config data) on active partition with proper loader entries.
- \bootmgr on active partition
You can use Windows recovery/install DVD/USB, go to repair command prompt:
bootsect.exe - to write PBR and MBR
bootsect /nt60 all /mbr - should do
bcdboot.exe - to repair/create BCD (and bootmgr)
bcdboot c:\windows - should do (assuming Windows is installed on c:)
To set a partition as active you can use diskpart.exe (or DiskManagement within Windows).
Windows boot seqeuence from hard disk is always:
- BIOS loads and executes MBR from first hard disk
- MBR loads and executes PBR from active partition
- PBR loads and executes bootmgr from active partition
- bootmgr reads BCD and displays boot menu (or when only one loader entry in BCD bootmgr loads and executes winload.exe and so on ....)