What happens if I deactivate Windows RT?

Question

Windows RT is, like any other OEM Windows product, preinstalled and preactivated on a PC. Most PCs running standard Windows have a product key label on the back (for desktops) or on the bottom (for laptops). Most other PCs that don't have a product key label instead come with recovery CDs that allow one to recover the OS to the original state if it becomes unusable for any reason. However, Windows RT PCs don't have any of that (at least the Surface doesn't; I'm not sure about other Windows RT devices). However, it is still possible to deactivate Windows RT by going into System Properties and then choosing the option to deactivate. If I do accidentally deactivate Windows RT like this, is there a way to get another product key to activate it again? I know that, for OEM copies of Windows, the key stored in the registry is the general key that the OEM used to preinstall Windows, not the specific key for my machine.

Answer 1

This script from XDA can be used to extract the key, just save it as .bat and run it.

::' Windows RT 8.0 Product Key Dumper by Myria of xda-developers.com
::' Original Windows 8.0 VBScript by janek2012 of mydigitallife.info
::' Batch+VBScript hybrid trick by dbenham of stackoverflow.com
::' Fix for keys starting with N by Osprey00 of xda-developers.com
::'
::' Windows RT doesn't let unsigned VBScript use WScript.Shell, which is
::' required in order to read the registry in VBScript.  So instead, we
::' have a batch file call reg.exe to do the registry lookup for us, then
::' execute the VBScript code.  Might as well do things this way, since
::' it would really suck to write this math in batch...

::' --- Batch portion ---------
rem^ &@echo off
rem^ &call :'sub
::' If we were run from double-clicking in Explorer, pause.
rem^ &if %0 == "%~0" pause
rem^ &exit /b 0

:'sub
::' Read the registry key into VBScript's stdin.
rem^ &("%SystemRoot%\System32\reg.exe" query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v DigitalProductId | cscript //nologo //e:vbscript "%~f0")
::'rem^ &echo end batch
rem^ &exit /b 0

'----- VBS portion ------------
'WScript.Echo "begin VBS"

' Get registry data that was piped in
RegData = ""
Do While Not WScript.StdIn.AtEndOfStream
    RegData = RegData & WScript.StdIn.ReadAll
Loop

' Remove any carriage returns
RegData = Replace(RegData, ChrW(13), "")

' Split into lines
RegLines = Split(RegData, ChrW(10))

' Sanity checking on data
If (RegLines(0) <> "") Or (RegLines(1) <> "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion") Then
    WScript.Echo "Got invalid header trying to run reg.exe"
    WScript.Quit(1)
End If

If Left(RegLines(2), 38) <> "    DigitalProductId    REG_BINARY    " Then
    WScript.Echo "Got invalid value list trying to run reg.exe"
    WScript.Quit(1)
End If

' Get hex string
HexString = Mid(RegLines(2), 39)
If (Len(HexString) Mod 2) <> 0 Then
    WScript.Echo "Got an odd number of hex digits in REG_BINARY data"
    WScript.Quit(1)
End If

' Convert to byte array
Dim ByteArray()
ReDim ByteArray((Len(HexString) / 2) - 1)  ' VBScript is just weird with array dimensions >.<

For i = 0 To (Len(HexString) - 2) Step 2
    ByteArray(i / 2) = CInt("&H" + Mid(HexString, i + 1, 2))
Next

Key = ConvertToKey(ByteArray)
WScript.Echo Key

' janek2012's magic decoding function
Function ConvertToKey(Key)
    Const KeyOffset = 52 ' Offset of the first byte of key in DigitalProductId - helps in loops
    isWin8 = (Key(66) \ 8) And 1 ' Check if it's Windows 8 here...
    Key(66) = (Key(66) And &HF7) Or ((isWin8 And 2) * 4) ' Replace 66 byte with logical result
    Chars = "BCDFGHJKMPQRTVWXY2346789" ' Characters used in Windows key
    ' Standard Base24 decoding...
    For i = 24 To 0 Step -1
        Cur = 0
        For X = 14 To 0 Step -1
            Cur = Cur * 256
            Cur = Key(X + KeyOffset) + Cur
            Key(X + KeyOffset) = (Cur \ 24)
            Cur = Cur Mod 24
        Next
        KeyOutput = Mid(Chars, Cur + 1, 1) & KeyOutput
        Last = Cur
    Next
    ' If it's Windows 8, put "N" in the right place
    If (isWin8 = 1) Then
        keypart1 = Mid(KeyOutput, 2, Cur)
        insert = "N"
        KeyOutput = keypart1 & insert & Mid(KeyOutput, Cur + 2)
    End If
    ' Divide keys to 5-character parts
    a = Mid(KeyOutput, 1, 5)
    b = Mid(KeyOutput, 6, 5)
    c = Mid(KeyOutput, 11, 5)
    d = Mid(KeyOutput, 16, 5)
    e = Mid(KeyOutput, 21, 5)
    ' And join them again adding dashes
    ConvertToKey = a & "-" & b & "-" & c & "-" & d & "-" & e
    ' The result of this function is now the actual product key
End Function

Answer 2

This Below Script reads the Unique Key from RT and not the OEM of the above code.

@echo off &setlocal
call :GetProductKey sWinProdKey
echo Windows Product Key: %sWinProdKey%
echo(
pause
goto :eof

:GetProductKey outVarName
setlocal EnableDelayedExpansion
set "sKeyChar=BCDFGHJKMPQRTVWXY2346789"
set "sRegKey=HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion"
set "sRegVal=DigitalProductId"

for /f "tokens=3" %%i in ('reg query "%sRegKey%" /v "%sRegVal%"') do set "sHex=%%i"

set /a "n = 52"
for /l %%i in (104,2,132) do set /a "aRegValue_!n! = 0x!sHex:~%%i,2! , n += 1"

for /l %%b in (24,-1,0) do (
  set /a "c = 0 , n = %%b %% 5"
  for /l %%i in (66,-1,52) do set /a "c = (c << 8) + !aRegValue_%%i! , aRegValue_%%i = c / 24 , c %%= 24"
  for %%j in (!c!) do set "sProductKey=!sKeyChar:~%%j,1!!sProductKey!"
  if %%b neq 0 if !n!==0 set "sProductKey=-!sProductKey!"
)
endlocal &set "%~1=%sProductKey%" &goto :eof