Boot requires C:\ while using E:\

simplefranco

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Oct 9, 2010
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Hello again, dear community.

I don't run to boot issues often as I don't tend to tweak with it much, but it's here...title sais it all.

I am using a Windows 7 system on a new hard disk, for around 2 months now. Here's the catch: I had a previsous Windows 7 installed on my C:\ drive, from an older computer. When I got the new one, let's call it E:\ I installed a Windows 7 on it, and everything went fine, so I could easily dual boot (the same OS) on both disks.

Now I was thinking of getting rid of my C:\ back to the old computer as I no longer need it. But right after taking it out, I got a "BOOT Error - Insert system disk". Did I forget something? I've backed up the settings from "bcdedit" and tried setting everything pointing to E:.

Here's the screenshot:
bcdedit.jpg


Now, I'm not sure if that's the right place to mess with the settings, but I found bcdedit while searching for boot.ini under Windows 7, so...forgive my ignorance if applied.

Help appreciated, thanks in advance.
 
Solution
Simplefranco

Don't worry, I'm pretty sure that I can solve this one.

Unfortunately it's late (for me), or I could re-write one of my lengthy expositions on boot orders. Well, unfortunately for me, fortunately for you. Davcon, I dual-booted the same OS for ages. Actually, quadruple at one point: XP - XP - DOS - Win7, when I first started playing with 7.

The short answer: Shut down and unplug the computer. Press the power on button to discharge the capacitors. Then remove the first drive, leaving only the new OS drive and the DVD drive in place. Boot to the Windows 7 DVD, choose to Repair an Existing Installation, and viola! It will now boot from that disk.

If you re-install the old disk, you will have to set up your...
Windows 7 creates a hidden partition that's about 100MB in size which is the actual boot partition. This partition contains the initial boot loader and some recovery tools you can use in the event that your OS becomes corrupted. During the boot process the boot loader from this recovery partition then loads the actual OS from the main partition that contains the full Windows 7 system.

When you install Windows, the install kit will try to put the recovery partition onto a different physical disk drive than the one that the main Windows 7 partition is on. The idea is that you can use it to boot and recover your OS from a backup even if the OS disk is dead. Unfortunately, most people expect that the OS partition itself to be the boot disk, and this causes problems such as the one you're describing.

When I install Windows 7 I physically disconnect all other drives so that the install program is forced to put both partitions on the same drive. This eliminates the problem.

Unfortunately, I know of no easy way to "move" the recovery partition once the install is done. The only sure solution I can offer is to re-install Windows 7 on the drive you want with all of the other drives disconnected.
 
Simplefranco

Don't worry, I'm pretty sure that I can solve this one.

Unfortunately it's late (for me), or I could re-write one of my lengthy expositions on boot orders. Well, unfortunately for me, fortunately for you. Davcon, I dual-booted the same OS for ages. Actually, quadruple at one point: XP - XP - DOS - Win7, when I first started playing with 7.

The short answer: Shut down and unplug the computer. Press the power on button to discharge the capacitors. Then remove the first drive, leaving only the new OS drive and the DVD drive in place. Boot to the Windows 7 DVD, choose to Repair an Existing Installation, and viola! It will now boot from that disk.

If you re-install the old disk, you will have to set up your BIOS to choose which disk it will boot from. I recommend putting the new one in a lower-numbered SATA slot, so that the BIOS will choose it whenever the BIOS is disturbed and loses your boot preferences.

===================================

OK, the exposition in brief, or if you really give a hoot you can search the forums for me on the subject of dual-boot. This applies to the Windows boot loaders; there are excellent 3d-party bootloaders that work differently. It also applies to BIOS, not the newer but rare UEFI or whatever it's called.

When your computer boots, the first thing to run is the BIOS, which lives on your motherboard. It looks for a disk that claims to be bootable, loads the MBR (Master Boot Record) from it, and tries to load the tiny loader program that the MBR points to. Note that if it fails to find a disk that claims to be bootable, or fails to find the MBR or the tiny little program, your boot will fail.

The program loaded from the MBR may or may not offer you a choice of OSes to boot if you have installed more than one. It will then take the partition you chose and load its PBR (partition boot record) and the small program that that points to, which will finally load your OS.

To make things easier to understand, if you look in the Disk Manager the partition that you booted off will be called the System Partition, and the partition with the operationg system will be called the Boot Partition. Honestly!

So what does this mean? Your first install put the MBR and second-stage boot stuff on the older drive. Your second install saw that there was a bootable disk and did not make the drive onto which you installed bootable. It just added the partition that you installed to the list of choices offered when the system boots from your old disk.

If you hadn't already started, all of us would agree with sminlal that you should have had only the installation disk in the machine when you did the second install. The only time that I remember disagreeing with sminlal is that I think that, if you install win7 on a machine with six blank drives in it and let it partition the drives, it will install the 100 MB hidden partition on the same drive as your installation partition. In either case, this drive will be the bootable one.

If the new drive with the already-installed Win7 on it is the only drive in the machine and is not bootable, when you run a repair off the DVD it will think to itself "holy excrement, this poor installation of Windows has no bootable disk to start from" and make the disk bootable. Fortunately or unfortunately, depending on your point of view, the repair will not be able to make the 100 MB hidden partition; that only happens if you install to a drive and let the installation process partition the drive.
 
Solution

simplefranco

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Oct 9, 2010
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Wow! Not only it was hilarious to read as it was extremely useful. Thanks WyomingKnot, I will give it a go whenever I can, which should be this weekend and let you know how it went.

By the way what's with discharging the capacitors?

Thanks again, cheers!
 

simplefranco

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Oct 9, 2010
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Just wanted to confirm it worked :bounce:
Unplugged the 'old' disk from the SATA port, started my Win 7 DVD as if I was installing it, and once it detects at least 1 OS, it will immediatly tell you there's an issue with the startup disk. Had to do it twice, don't know why; once it shut down after repairing, but when I did it again a new screen popped up with several repair tools (mem diagnosis, cmd terminal and the first one: windows startup repair)

Thank you very much :)
(Shock-free)