Dual-boot Repair utility for Windows 8, Windows 7 and Vista

Dual-boot Repair will automatically fix dual-boot systems based on Windows 7, Windows 8 or Vista with Windows XP, Vista or Windows 7/8 as second operating system.
Many users are willing to move to Windows 7/8 from XP or Vista but want to keep their old system for many reasons. Dual-booting is a solution to have two or more OS installed side by side. A dual-boot system is also useful when testing software in different environments.
You have installed Windows 7/8 or Vista after having Windows XP or Vista on your system than everything should be OK. At boot time you will have the choice to boot either Windows XP/Vista or Windows 8/7/Vista. The only small problem here is that the boot menu entry for XP is called "Earlier version of Windows". This can be solved easy when in Windows 8/7/Vista by renaming the entry.
You have installed Windows XP after having Windows 8/7 or Vista and you can no longer boot into Windows 8/7/Vista. The problem is that the boot environment of Windows XP has replaced that of Windows 8/7/Vista. Installing an earlier Windows version when already having a later Windows version installed causes booting problems for the system installed earlier.

Repairing your dual-boot or multi-boot system is a simple one-click task using the Automatic Repair option of "Dual-boot Repair" utility.

The automatic repair option will recreate/repair Windows 8/7/Vista BCD and the boot environment, even in a multi-boot system, and allow the user to boot into Windows 8/7/Vista. The existing Windows 8/7/Vista Boot Configuration Data store - the BCD - will be saved, if present, in case something goes wrong.
So let's start.
Download and install Visual BCD package. Download latest Visual BCD version 0.9.3.1 here
Run "Dual Boot Repair". Click on "Automatic Repair". Confirm.
That's it !
Now you will be able to boot into Windows 8/7/Vista.
Later when in Windows 8/7/Vista you can add a loader entry for Windows XP or Vista installed on disk (if entry not already present in BCD).
Automatic repair fixes or recreates the latest boot environment on active partition. The boot environment for Windows 8/7/Vista consists of:

1. MBR and PBR (Master and Partition Boot Record) - repaired by using Windows bootsect.exe utility.
2. bootmgr - Windows 7/Vista boot manager.
3. \boot folder which includes the BCD file/store. (2 and 3 are repaired by using Windows bcdboot.exe utility)

bootmgr and \boot folder with BCD on active partition are the files needed to display the boot-menu.
Advanced options for repairing a dual boot system:
- "Repair BCD" is based on bcdboot.exe utility and can be used to fix BCD file/store.
- "Import and Export BCD" are based on bcdedit.exe.
- "Repair Boot Records" is based on bootsect.exe and can fix the MBR (master) and PBR (partition) boot records.
- "Disk Management" is a shortcut to Windows Disk Management.
- "Admin console - bcdedit" is a shortcut to command prompt with administrative rights. On clicking the command bcdedit is executed to list existing BCD entries.
(bcdedit.exe, bootsect.exe and bcdboot.exe are Windows utilities - they are installed in Visual BCD folder to assist the repair process)
Detailed advanced repair options help
Now let's focus on how to attach Windows 8/7 recovery environment to the advanced boot options as Windows 8/7 BCD repair (bcdboot.exe utility) does not care about this.

 "Repair Your Computer" is missing as a boot choice in Advanced Boot Options (on F8 key).

The utility that comes with Windows 8/7 for dealing with recovery is 'ReAgentC.exe".
The file containing Windows 8/7 Recovery environment is "WinRe.wim" and usually resides in the system folder "\Windows\System32\Recovery". If you don't have the Winre.wim file you can extract the file "Boot.wim" from your installation DVD (or recovery CD) and place it under the mentioned system folder and name. (Download link for 32-bit and 64-bit version of Windows 7 recovery files: download Windows 7 Recovery files)

1. Open a command prompt with administrative privileges.
2. Type command reagentc /disable.
3. Type command reagentc /enable. (Eventually reboot if the command reports an error and try again.)

You can examine with command reagentc /info the current state of recovery environment settings.
You can view the result of the commands above with Visual BCD Editor. You will see that there is a new "Windows Recovery Environment" loader. This loader is linked by element "Recovery Sequence" of  Windows 7 loader. The Windows 7 loader element "Auto Recovery Enabled" is also present and set to true. The recovery loader and the elements mentioned above are added by reagentc /enable command.
You can rename the loaders to your choice for example "Windows 7" loader could be renamed to "Windows 7-32" or "Windows 7-64" or whatever you like so the boot-menu will look better and suit your taste.