Restore Multiboot Options In Windows 7

Repair the MBR to restore Windows 7 to your Multiboot Options

Each time you install a version of Windows, it rewrites the MBR to call its own boot loader. If you install Windows 7 (or Windows Vista) as a second operating system on a PC where Windows XP is already installed, the Windows boot menu incorporates the options from the older boot menu. But if you install a fresh copy of Windows XP (or Windows Server 2003) on a system that is already running Windows 7, you’ll overwrite the MBR with one that doesn’t recognize the Windows 7 boot loader. To repair the damage, open a Command Prompt window in the older operating system and run the following command from the Windows 7 DVD, substituting the letter of your DVD drive for X here:

    X:\boot\ bootsect.exe /nt60 all

Now Restart your PC. It will boot to Windows 7. Now  open your CMD and type these commands.

    C:\Windows\system32\Bcdedit /create {ntldr} /d "Earlier Versions of Windows OS"
                     Note: In this command, Earlier Versions of Windows OS can be any text that you want. It's a Description of the OS.

    C:\Windows\system32\Bcdedit /set {ntldr} device partition=D:
                     Note:  In this command, D: is the drive letter for the active partition.

    C:\Windows\system32\Bcdedit /set {ntldr} path \ntldr

    C:\Windows\system32\Bcdedit /displayorder {ntldr} /addlast

Now you can find your older versions of Windows.