Question : XP Pro/Vista Dual Boot

Hello.  I have a laptop that I setup to dual boot XP Pro and Vista.  Had to reinstall XP Pro and now no longer have the option to boot vista.  I tried modifying the boot.ini file and was not successful (as I recall, the option to boot vista displayed before the boot.ini was processed).  Please advise.  Thanks!

Answer : XP Pro/Vista Dual Boot

If you are dual booting Windows XP and Windows Vista on your computer and due to problems are forced to repair or reinstall the XP partition, you may run into the problem described in this Microsoft article:
This MSKB article explains the problem:

http://support.microsoft.com/default.aspx?scid=kb;en-us;919529
Windows Vista no longer starts after you install an earlier version of the Windows operating system in a dual-boot configuration

The problem is that Windows Vista no longer uses the old boot loader used by Windows XP. When you reinstall XP, Setup overwrites everything from the MBR (the Master Boot Record), the boot sector, and the boot files, and thus loses communication with the installation of Vista, so you will only be able to boot into XP.  

Windows Vista uses a new Boot Configuration Database (BCD.)  This contains a boot menu and information about all operating systems installed on the computer.  In XP, the BIOS loads the Master Boot Record, which contains the partition table and some boot execution code that searches the partition table to find which partition is active and then passes control to its boot sector.  That boot sector loads a hidden file called NTLDR, which looks at the Boot.ini file to find which operating systems are installed.  But Vista, after the MBR and boot sector are loaded, then executes a boot manager called Bootmgr.exe that is hidden in the \Boot folder.  Bootmgr will look at the BCD file in order to determine what operating systems are present on your computer.

The article above gives information on how to use a program called BcdEdit to restore operation of both versions of Windows that you are using.  It also gives instructions on the correct way to install a dual boot system, and how to remove Windows Vista from a dual booting system.

This web page gives more information on the Vista boot loader and the BcdEdit utility:

http://www.windowsbbs.com/showthread.php?t=55153
Info on Vista's New Boot Loader

If BcdEdit seems a bit too complicated to use, you can try this free utility, called VistaBootPro:

http://www.vistabootpro.org/

Install it in XP and run it to restore your dual boot.

There is an online documentation for it here:

http://www.pronetworks.org/forum/viewtopic.php?t=78186
VistaBootPRO 2.0 User Guide