Drive Letter assignment for OS, want multiple OSs to think they are C:

Hi All

First post here.

This is the system that I used to have. An SSD with XP32, and another HDD with Win7x64. I first started with XP and then later installed 7. When I installed Win7 it called the partition that it was installed on "C:" (even though the XP installation claimed its partition to be C:). I set up a BCD (on the SSD) to allow me to boot into either XP (which I believe it did by looking at the boot.ini on that drive) or to boot into Win7 using pointers in the BCD? (I am not so familiar with how BCDs and MBRs work). So long story short, both OSs thought that they were installed on C: and everything was fine, each saw the other partition as D:. So all the programs and everything all pointed to C:, because the C: designation was relative at that point.

Now I just got a larger SSD and I wanted to image both the OSs onto the new SSD (in separate partitions). Seeing as the new SSD had no MBR or BCD, once both the OSs were on it, I had to build a BCD. When bootrec.exe was scanning the OSs it found 2 Win7 installations (one from the HDD and one from the SSD). I asked it to create pointers to both and figured that I would use something else to create a pointer to the XP installation later. What happened is that it considered the HDD Win7 to be C: and the SSD Win7 to be D:. The OS would boot from the SSD but kept looking to C: to run programs, because the image that it came from used to think that it was C: and all the pointers for executables and etc were to C:.

Then i tried to remove all the other drives and just have the new SSD with the two OSs. This time when I built the BCD it would boot into Win7 but claim that this was not a genuine installation and give me a bunch of other BS.

That was rather long winded.

So what I would like to know is. Is it possible to have two OSs on separate partitions on the same drive that each think they are C: when they are running. This way everything would be great and I could used my images that I have. I know one solution would be to install Win7 from scratch, but I am trying to avoid doing that (I dont know if it would think of itself as C: but at least the pointers to programs and everything would be to the correct drive and partition since everything would be reinstalled).

The conventional use of Windows and other OSes dictated that you can have only one drive letter per partition [each HDD needs at least one partition], i.e. can't have two C: drivers. Check your BIOS, the 0 or 1 drive is usually the boot drive [first drive scanned for bootable files] and gets the letter C:. But the newer computers may have changed that.

I'd think it possible to install two versions of Windows on different partitions on the HDD and from all I've seen and read it has been best to install the oldest OS first and newest OS last. I haven't tried installing Win7 after Win8 yet.

An entirely unnecessary mess that could have all been avoided if you'd posted a screenshot up of your Disk Management - Post a Screen Capture Image so we could have given you the steps to image both of the OS's over to the new SSD so that they maintain the Dual Boot, just as we've done successfully tens of thousands of times here before.

If possible plug it all back in as it was and if it still works correctly post back the needed screenshot.

If not possible, then have you imaged both the XP and the Win7 onto the same SSD? If so why is the old Win7 HD still plugged in and being discussed as an issue with its drive letter?

Once you've imaged both OS's to the new SSD - if that is indeed your goal - you'd unplug the old drives and go about making sure the new SSD can boot on its own. If one or both of the OS's will boot then post back a screenshot of Disk Mgmt (preferably from Win7) so we can see how it is now configured, what may need adjusting, and how to add the other OS to a Dual Boot if that's needed.

If neither OS can boot then download http://www.partitionwizard.com/download.html ISO, burn to CD with Windows Image Burner, boot to take a camera snap of the full drive map showing all listings, post back using paper clip icon in reply box.

It is correct that each OS will view itself as C when Win7 is correctly installed second to XP. But XP is normally still booting the Dual Boot if you use a Windows Boot menu. Wiser on separate HD's to install with the other unplugged, use the BIOS to boot your choice of HD's so they remain independent. But what matters now is which is marked System Active signifying it is booting the System. If XP has lost the System flag then it's easiest to move it to Windows 7 to add XP using EasyBCD. This is done by marking Win7 partition Active to run 3 separate Startup Repairs.

Thanks for the responses. I can indeed plug everything back in and make it work as it used to.
Here is a screen capture of disk management before I made any changes:

Here is a screen capture of disk management after I unplugged an extra drive and plugged in the new SSD, which has both the images on it. (This is the system as its currently booted)


I did image both operating systems onto the new SSD, each partition is named after the operating system on it. I have also tried unplugging all drives except the new SSD. Then I ran the RE from the windows 7 disc to make the drive bootable with bootrec (and possibly bcdedit). It found the Win 7 installation but indicated that it was drive D. So now it boots straight to 7 (skipping XP, which I was planning on adding later eith easybcd). But the issue is that the OS boots me into a temporary user mode, Im assuming that this is because its booting off of D: but thinks that all the executable and user directories are on C:. I cant even run basic programs like regedit or disk managment because its looking for the executable in the wrong place.

The old HDDs should not have been discussed as an issue, I was just relaying all the steps that I had gone through. I am happy to fix the dual os booting issue wiht just the new SSD plugged in.

I really appreciate the help and prompt responses.

I used DriveImage XML to Image.

When you say boot into the original installation which OS are you referring to? The Currently booted Win_7 installation is on the partition that appears as C: in the seconds screenshot.

Then I see that you are asking me to point the "Fix OS drive letter" to the G: Paritition (which is the new Win7 installation that I would like to use). Then to click fix.

Thank you.
Before I do this may I ask, will this affect the boot sector (MBR or BCD) on either Disk 0 or Disk 1 from my second screen shot? (Really the boot sector is on Disk 1, that is what I am concerned about, as it is my failsafe that I am currently running on).

Sorry to ask so many questions but what exactly will the steps that you outlined do. I am very grateful that you posted them, but I have so many empty spots in my knowledge of OSs that I would like to fill in.

Will it modify the drive letter assignment? If so, where is the drive letter assignment stored?

Also, what exactly did the imaging program miss, what else should it have done?

So I did it and a prompt window popped up saying the system cannot find the file specified.

*edit - Sorry posted that in error, was not running as admin