Windows no longer starts after you install an earlier version of the windows operating system in a dual-boot configuration

Hi Mark Green1,


Since  this article is for Windows Vista and Windows XP partition that is the reason you are getting this error.
We need to boot in to Windows XP first and run some commands and then get back to Windows 7 and then follow this article.
So let us start over.

Step 1.
In the WinRE (Windows Recovery Environment)
Use Bootsect.exe to restore the Windows XP MBR and the boot code that transfers control to the Windows Boot Manager program. To do this, type the following command at a command prompt: Drive:\boot\Bootsect.exe /NT52 All

Step 2.
After running the above command now you will boot to Windows XP and Windows 7 will be missing.

1. Open a CMD prompt on Windows XP and run the following commands,
replacing “C:” in the commands with the drive letter for the system partition:

Attrib –h –s –r c:\ntldr
Attrib –h –s –r c:\bootmgr
ren c:\ntldr ntldr.old
copy c:\bootmgr ntldr

2. Restart the computer. The next boot should show the Windows 7 boot manager menu. Use F8 to start into WinRE.
3. Open a command prompt in WinRE and run the following commands:
4. bootsect /nt60 SYS
5. Copy c:\ntldr.old c:\ntldr (overwrite when prompted)
6. Restart the computer

Step 3.
Then continue with the BCDEdit steps in article 919529 to add Windows XP to the Windows 7 boot menu.
Use Bcdedit.exe to manually create an entry in the BCD Boot.ini file for the earlier version of the Windows operating system. To do this, type the following commands at a command prompt.

Note In these commands, Drive is the drive where Windows 7 is installed.

    * Drive:\Windows\system32\Bcdedit /create {ntldr} /d "Description for earlier Windows version"

      Note In this command, Description for earlier Windows version can be any text that you want. For example, Description for earlier Windows version can be "Windows XP" or "Windows Server 2003".
    * Drive:\Windows\system32\Bcdedit /set {ntldr} device partition=x:

      Note In this command, x: is the drive letter for the active partition.
    * Drive:\Windows\system32\Bcdedit /set {ntldr} path \ntldr
    * Drive:\Windows\system32\Bcdedit /displayorder {ntldr} /addlast

For additional help on Step 3, refer to the following article.
http://support.microsoft.com/kb/919529

Step 4.  Restart the computer.
Now you should get both Windows 7 and Windows XP option while booting.


Hope it helps.

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Thanks and Regards:
Shekhar S - Microsoft Support.

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