Boot Drive Only Successfully Boots with Second Hard Drive

Although my Disk 0 (see attached Computer Management jpg) displays itself as the boot drive, it will not boot up alone. I must power up a second drive (labeled Disk 1) to view Disk 0. I understand the need to use the BIOS to point to the Boot Drive and Boot Priority, and have done this each time.

1. This is not a BSOD issue.
2. I have multiple W7 operating systems installed. One on Disk 0 and one on Disk 1. I am offered a choice when booting from Disk 1, to choose operating systems and I select the one located on Disk 0. (Verified by the jpg file.)
3. But with only the Disk 0 receiving power, I get a message that the drive will not boot unless I insert a bootable disk.
4. However, with both the Disk 0 and the Disk 1 drive receiving power, I manually change the BIOS to point to Disk 1 to allow both drives to be viewed successfully.

I would just like to use Disk 0, but since it will not boot by itself, (even though it shows it is the bootable drive), I must be doing something wrong. How can I use only Disk 0?

The Boot flag only means which is currently booted. System flag is where the boot files are loaded.

Do as Rich suggests above but mark C Active first so the installer Repair function will know where to write the System Boot files, then set Disk0 first to boot in BIOS setup after unplugging Disk1.

Within 3 separate Startup Repairs from DVD or System Repair Disk Disk0 should boot on its own.

Power down to plug back in the other HD and boot it when needed using the one-time BIOS Boot Menu key given on first boot screen. This keeps the HD"s independent to come and go as you please. Remove any unneeded Boot menu entries in EasyBCD Edit OS Menu tab.

whs said:

You can also just move the bootmgr from disk1 to C with 3 clicks: Bootmgr - Move to C:\ with EasyBCD

System Reserved will lose the ability to boot the OS on Disk1.

This will also not add System Recovery Options to the F8 Advanced Boot Options on Disk0.

The advantage of having separate HD's is to boot either via the BIOS Boot order or one-time BIOS Boot Menu key. This keeps them independent to come and go as you please.

However if you don't like this arrangement you can install EasyBCD to the Primary HD to add the other and they should both retain independent System boot files if you repair it as suggested first.

Success! Using both hard drives, I first made my C: drive on Disk 0 as Active (as described above). I then disconnected Disk 1 and tried the boot sequence with only Disk 0 (expecting to use my Repair Disk three times). But I received the error: "Bootmgr is missing. Press Cntl-Alt-Del to restart" so I was prevented from doing a Startup Repair. There indeed was no Bootmgr on Disk 0. So I transferred the boot files from Disk 1 by using EasyBCD as described at the link. It was not necessary for me to use Startup Repair after transferring Bootmgr. What's the explanation then?

Bootmgr is missing error is to be expected when booting after changing the Active flag.

As stated you need to boot into the Win7 DVD or Repair CD to run Startup Repairs x3.

Booting into a disk is not affected by Bootmgr is missing at all which refers only to the HD set first to boot which still needs System boot files.

Moving Boot files using EasyBCD is fine but as I said earlier you may not be able to boot the other HD now and it does not write the System Recovery Options to F8 Advanced Boot TOols menu, which is one of the things Startup Repair does.

You can however add the other OS if still needed using EasyBCD.

Ahhh. I had wrongly expected that I would be given a choice to boot from the Repair Disk (which I had already inserted in the drive). I should have instead changed the BIOS to force it to boot from the DVD disk. My mistake. I haven't tested to see if a separate boot function is lost on the other drive, but no harm is done because I will use that drive for data anyway. Many thanks for the solutions.