Per visualizzare il Product Key inserito all’atto dell’attivazione del sistema operativo è possibile usare uno script Powershell (o WSH per i computer con XP/2003). Ecco come fare.

Qualora non aveste mai usato uno script powershell comparirebbe quest’errore

Per ovviare al suddetto errore bisognerà verificare e modificare temporaneamente lo stato della policy di esecuzione degli script con il seguente comando:
get-executionpolicy
il risultato dovrebbe essere restricted (cioè non è possibile eseguire script)
Quindi potete lanciare i seguenti comandi:
set-executionpolicy -bypass
[Lanciare lo script che vedremo in seguito]
set-executionpolicy -restricted (o RemoteSigned, AllSigned o qualsiasi altro rilevato dal primo comando)

ECCO LO SCRIPT IN POWERSHELL:
function Get-WindowsKey {
## function to retrieve the Windows Product Key from any PC
## thanks to by Jakob Bindslet (jakob@bindslet.dk)
param ($targets = ".")
$hklm = 2147483650
$regPath = "Software\Microsoft\Windows NT\CurrentVersion"
$regValue = "DigitalProductId"
Foreach ($target in $targets) {
$productKey = $null
$win32os = $null
$wmi = [WMIClass]"\\$target\root\default:stdRegProv"
$data = $wmi.GetBinaryValue($hklm,$regPath,$regValue)
$binArray = ($data.uValue)[52..66]
$charsArray = "B","C","D","F","G","H","J","K","M","P","Q","R","T","V","W","X","Y","2","3","4","6","7","8","9"
## decrypt base24 encoded binary data
For ($i = 24; $i -ge 0; $i--) {
$k = 0
For ($j = 14; $j -ge 0; $j--) {
$k = $k * 256 -bxor $binArray[$j]
$binArray[$j] = [math]::truncate($k / 24)
$k = $k % 24
}
$productKey = $charsArray[$k] + $productKey
If (($i % 5 -eq 0) -and ($i -ne 0)) {
$productKey = "-" + $productKey
}
}
$win32os = Get-WmiObject Win32_OperatingSystem -computer $target
$obj = New-Object Object
$obj | Add-Member Noteproperty Computer -value $target
$obj | Add-Member Noteproperty Caption -value $win32os.Caption
$obj | Add-Member Noteproperty CSDVersion -value $win32os.CSDVersion
$obj | Add-Member Noteproperty OSArch -value $win32os.OSArchitecture
$obj | Add-Member Noteproperty BuildNumber -value $win32os.BuildNumber
$obj | Add-Member Noteproperty RegisteredTo -value $win32os.RegisteredUser
$obj | Add-Member Noteproperty ProductID -value $win32os.SerialNumber
$obj | Add-Member Noteproperty ProductKey -value $productkey
$obj
}
}

E QUELLO CON WINDOWS SCRIPTING HOST

const HKEY_LOCAL_MACHINE = &H80000002
strKeyPath = "SOFTWARE\Microsoft\Windows NT\CurrentVersion"
strValueName = "DigitalProductId"
strComputer = "."
dim iValues()
Set oReg=GetObject("winmgmts:{impersonationLevel=impersonate}!\\" & _
strComputer & "\root\default:StdRegProv")
oReg.GetBinaryValue HKEY_LOCAL_MACHINE,strKeyPath,strValueName,iValues
Dim arrDPID
arrDPID = Array()
For i = 52 to 66
ReDim Preserve arrDPID( UBound(arrDPID) + 1 )
arrDPID( UBound(arrDPID) ) = iValues(i)
Next
'
Dim arrChars
arrChars = Array("B","C","D","F","G","H","J","K","M","P","Q","R","T","V","W","X","Y","2","3","4","6","7","8","9")

'
For i = 24 To 0 Step -1
k = 0
For j = 14 To 0 Step -1
k = k * 256 Xor arrDPID(j)
arrDPID(j) = Int(k / 24)
k = k Mod 24
Next
strProductKey = arrChars(k) & strProductKey
'
If i Mod 5 = 0 And i <> 0 Then strProductKey = "-" & strProductKey
Next
strFinalKey = strProductKey
'
'
'
strComputer = "."
Set objWMIService = GetObject("winmgmts:" _
& "{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2")
Set colOperatingSystems = objWMIService.ExecQuery _
("Select * from Win32_OperatingSystem")
For Each objOperatingSystem in colOperatingSystems
strOS = objOperatingSystem.Caption
strBuild = objOperatingSystem.BuildNumber
strSerial = objOperatingSystem.SerialNumber
strRegistered = objOperatingSystem.RegisteredUser
Next
Set wshShell=CreateObject("wscript.shell")
strPopupMsg = strOS & vbNewLine & vbNewLine
strPopupMsg = strPopupMsg & "Build Number: " & strBuild & vbNewLine
strPopupMsg = strPopupMsg & "PID: " & strSerial & vbNewLine & vbNewLine
strPopupMsg = strPopupMsg & "Registered to: " & strRegistered & vbNewLine & vbNewLine & vbNewLine
strPopupMsg = strPopupMsg & "Your Windows Product Key is:" & vbNewLine & vbNewLine & strFinalKey
strPopupTitle = "Informazioni licenza Microsoft Windows"
wshShell.Popup strPopupMsg,,strPopupTitle,vbCancelOnly+vbinformation
WScript.Quit