Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\OSUpgrade]
"AllowOSUpgrade"=dword:00000000
"ReservationsAllowed"=dword:00000000

[-HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\OSUpgrade\State]

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\GWX]
"DisableGWX"=dword:00000001