Most folks will tell you that it’s not possible to upgrade a machine runnning Windows XP Professional based operating system to a Windows Vista Home based operating system.

Microsoft say that you can only upgrade Windows XP Professional to Windows Vista Business or Windows Vista Ultimate.  Well, they say you can upgrade from Windows XP Professional to Windows Vista Home by performing a “Clean Install”.  Wiping your hard disk drive to reinstall is  definitely not upgrading in my books.  Anyway, this advice is wrong.  It IS possible to upgrade, retaining all of your documents and settings, installed applications etc.  It’s not straight forward, it’s not pretty and it’s not perfect.  But, I’ve done this for a customer and it does work.

Here are the things I needed:

• A PC running Windows XP Professional Edition that needs to be upgraded to Windows Vista Home (or Home Premium) 
• Windows XP Home Edition CD
• Windows XP Home Edition Licesnse Key
• TweakNT
• Windows Vista DVD
• Windows Vista Home or Home Premium License Key

When I did this, I had to move the installation to a new motherboard and CPU at the same time.  So, the first step was to startup the PC as it was and change the IDE Driver to “Standard Dual Channel PCI IDE Controller”.  This will stop you getting a blue screen when starting up on the new motherboard.  As I was moving from an Intel to an AMD based system, I also had to manually remove the file Intelppm.sys from the c:\windows\system32\drivers directory.  Without doing this, Windows would come up with a stop 7B blue screen on booting.  To do this, I used a boot disk with NTFS capability.  Once I had done this, I could start up Windows XP Professional on the new motherboard and CPU.  Once this had loaded, I setup the drivers for the new hardware.

It turns out that the old version of WinZip (6.1) that the user had installed was not compatible with Vista so that too had to go.  Unfortunately the uninstallation program didn’t remove the c:\program files\winzip directory which in this case continued to block the Windows Vista upgrade.  This directory had to be manually deleted too.

Now the fun part.  I had to run TweakNT and change the Windows XP Installation type to Windows XP Home.  The system was rebooted as requested by the program.  Note that doing this will leave your system in a unbootable configuration.  If you try and boot into Windows XP, you will get a license error.  So, you have to boot from your Windows XP Home edition CD and perform a repair installation.  Use the temporary Windows XP Home edition license key (you won’t need to activate before installing Vista).  Once your installation has been repaired and several reboots later you will have a system running Windows XP Home. 

From here, you can now run your Windows Vista CD and perform the upgrade to Windows Vista Home or Home Premium.

Was it worth all the effort?  Well to the customer it was.  For me, the fun was finding the answer to a seemingly impossible scenario

Have fun…

P.S.  Backup all important files before attempting to recreate any of the above!

P.P.S. Please do not ask me where to find TweakNT.  It can be found if you look carefully.  It’s easily available via various P2P networks.  YMMV.