A. Once you have a VHD mounted as a drive letter, you can check the editions you can upgrade it to using the /Get-TargetEditions switch of DISM. (See this FAQ for help mounting a VHD.) The VHD I'm checking is running Windows 7 Home Premium. As you can see, it shows I can update it to Ultimate or Professional.

D:\Documents\Scripts>dism /image:w:\ /get-targeteditions

Deployment Image Servicing and Management tool
Version: 6.1.7600.16385

Image Version: 6.1.7600.16385

Editions that can be upgraded to:

Target Edition : Ultimate
Target Edition : Professional

The operation completed successfully.

The order of operating systems for the purpose of upgrading to a higher version is:

  1. Windows 7 Starter
  2. Windows 7 Home Basic
  3. Windows 7 Home Premium
  4. Windows 7 Professional
  5. Windows 7 Ultimate