To Install Dual Operating Systems (Window 7 & XP)

When you cannot boot to Windows XP after installing windows 7

1.Open an elevated command prompt.
2.Type the following to create a boot loader for Windows XP.
bcdedit /create {ntldr} /d "Windows XP"
3.Type the following to set the device to where Windows XP is installed. I used D: in this example. Replace it with the drive letter of your XP installation.
bcdedit /set {ntldr} device partition=D:
4.Type the following to set the path.
bcdedit /set {ntldr} path \ntldr
5.Type the following to add this boot loader to the boot up screen.
bcdedit /displayorder {ntldr} /addlast
6.Reboot the computer.