If Windows Update or Genuine check is complaining about an non-genuine install of Windows and you have a legit key it can be changed by following these steps:

  1. Change one of the values in this key to deactivate Windows: HKLM\\Software\\Microsoft\\WindowsNT\\CurrentVersion\\WPAEvents
  2. Run this command-line to force a reactivation: %systemroot%\\system32\\oobe\\msoobe.exe /a
  3. Choose the option: Yes, I want to telephone a customer service representative to activate Windows
  4. Click: Change Product key, after which the programme can be closed - the wizard does not have to finish.

You may need to reboot before you can start using Windows Update etc.

See Also

KB328874

Registry

Category:Windows