just do this: (i posted a tutorial)
Just Place your Vista DVD/CD int he drive in VISTA and now go to start menu, all programs , accessories , right click on command prompt
and click on run as administrator
now type these commands :
Use Bootsect.exe to restore the Windows Vista 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 –NT60 All
In this command, Drive is the drive where the Windows Vista installation media is located.
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 Vista 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 \ntldrDrive:\Windows\system32\Bcdedit –displayorder {ntldr} –addlast
*www.thinkdigit.com/forum/showthread.php?t=52686
and remember this is an M$ certified method.. so most safer one..