Dual Boot Vista and XP (Vista already installed)

Couple of days ago, a friend of mine asked if I can teach how to install Windows XP on a Vista machine and have it dual boot.

Found a good tutorial for her, so I might as well post it here too for my collection ;D

So here goes:

You need :- Windows Vista and Windows XP installation discs.

First off, please double check that your SATA controller is set to "IDE" in your BIOS so that we won't need to need a floppy drive and disk to install XP.

Step 1 - Partition the Drive:

• Right click Computer under the start menu and choose "manage"
  


• Right click on the drive you want to partition, or your Vista drive and select "Shrink Partition"


• The amount you needed to shrink the partition is the amount of space used for the XP partition, so I would suggest making it at least 3-4GB in size, as a full XP installation will take 1.5GB on it's own.


• Now right click on the unallocated memory and select new basic partition.
  


• Choose NTFS file system, and name it anything you like, usually "XP" or "WinXP" for me


• Click next on the rest of the screens and finish.

Once the formatting is finished you will have something like this:

* this new partition is where your XP installation will go, so take note of it's location, in case there are multiple partitions on the drive (there will now be atleast 2).

Steps 2 - Install XP:

• Now that XP has installed, it attempts to boot for the first time... all goes fine, video settings, networking, then the lovely welcome screen as usual.
  
  You restart, expecting a boot loader screen... followed the tutorial this far, and now you seem to only have XP... well not quite, I wouldn't leave you hanging without giving you a proper dual boot.
  
  
  here lies the only real issue with installing XP after Vista, but it's a quick fix if you have your Vista CDs/DVD handy.
  
  The problem is that Vista and XP use different boot loader utilities in the MBR (Master Boot Record) of your hard drive. XP does not recognize Vista, but Vista will recognize XP, so we need to remove the boot loader that XP just put in with the old Vista boot loader. So restart once more, but this time with your Vista disc in the drive.

Step 3 - Fix Boot Loader:
Boot up computer with Vista installation disc.
Vista will load the GUI files, and then display the loading splash screen.

• Click "Next" on the first screen


• Once the "Install Now" menu (do NOT click Install Now) choose "Repair Your Computer":
  


• You will be prompted to choose the OS to repair. Don't worry if Vista is the only OS that shows up, even after a search.
  
  
  click "Next"


• choose to open a "Command Prompt":
  


• Type in the command prompt the following 2 lines (separately):
  Bootrec.exe /fixMBR
  Bootrec.exe /fixBoot
  


• Close the prompt and restart


• Now that Vista controls your boot loader, the process is mostly finished, now we need to inform Vista that XP is installed, as to enable the boot loader selection screen.

Step 4 - Edit boot.ini:
In Vista, the boot.ini is not editable directly, as the file itself is hard to locate, so we will be modifying it through "Boot Configuration Data Store Editor" bcdedit.exe:
(Just as an explanation, the loader type for XP is an NT Loader, hence the use of ntldr)

• First open a command prompt with administrative privilages (right-click and choose "run as administrator")
  *Note the following 2 answers from bcdedit for each item are acceptable:
  "The Operation Completed Successfully"
  "The Specified Entry Already Exists"
  
  Be sure to type each line carefully (replace C in the first line with the drive containing your Vista installation):
  bcdedit –set {ntldr} device partition=C:
  bcdedit –set {ntldr} path \ntldr
  bcdedit –displayorder {ntldr} –addlast
  bcdedit -set {ntldr} description "Microsoft Windows XP"
  
  The completed bcdedit file should resemble this:
  


• This will correctly add XP to your boot sequence, and even name it properly instead of "Earlier Version of Windows"


• The displayorder line also allows the entry to be visible under the advanced settings of your computer properties.
  

Vista is the default boot, if you wish to change this to XP it can be done by setting {current} to addlast, or under the computer -> properties -> advanced settings.

If all done properly, XP and Vista will dual boot properly!


Credits and big thanks to William Wilson of </dream.in.code> for this great tutorial :D