With the release of Windows Vista comes a surprising change to the way the upgrade version works.
Unlike previous version of Windows, you can no longer wipe out your existing Windows installation and install a fresh install of Vista with the upgrade DVD. Instead, your upgrade version on top of the previous version of Windows you have.
This change will help cut down on the number of people buying the wrong version of Windows Vista but creates a huge annoyance for any power user that wants to start fresh with a new Windows operating system.
Users that already wiped their previous Windows installation with the Windows Vista install disk while installing the upgrade version are in for a surprise when they try to active Windows. It won’t activate! Why? Windows is looking for a full version product key because the user did not install the upgrade version of Windows Vista from within a previous version of Windows.
Users that want to perform a fresh Windows Vista install the traditional method are not going to be able to active their upgrade copy. If you still want to do a clean install with Windows Vista so that your XP settings and junk does not get ported over, there is a new method that will allow you to do a clean install and activate your upgrade version.
Fresh Windows install with the upgrade version of Windows Vista
- Use your Windows Vista DVD to wipe out your previous Windows installation and install Vista without a product key as shown here.
- After you have Vista installed, use your Windows Vista DVD again and perform an upgrade using your upgrade product key. Yes, upgrading Windows Vista to Vista works.
- Your upgrade key will now activate Windows and you will have a clean install of Windows Vista.
Source:→ TweakvistaMicrosoft Windows Vista, Ugrade, Install, Fix, Tips