When you insert a Windows Vista 64-bit DVD within a 32-bit operating system, and setup is launched, the operation is unsuccessful, and you receive the following error message:
Setup cannot run on this version of the Operating System. To install Windows please try booting from the install media.
When you try to upgrade a computer’s operating system from the 64-bit version of Windows XP Professional (x64) to a 64-bit version of Windows Vista, the upgrade is disabled. Note
If you have a 64-bit version of Windows Vista installed, you can upgrade to an allowed 64-bit version of Windows Vista. For example, you can upgrade Vista Home Premium to Vista Ultimate.