Re-activating Microsoft Products

Last updated: January 30, 2023
Audience: IT Staff / Technical

After you’ve restored the system state, you’ll find that your computer has lost its activation. And what’s worse, it won’t automatically reactivate. To fix this, you’ll need to follow these steps:

Step 1:  First, you’ll need to determine what the product key was. Windows is confused about what state it’s in, so you’ll need to give it the product key again. To find out the product key, use one of the product key viewers widely available online or use this powershell:

# create table to convert in base 24 
 # Read registry Key 
 $value = (get-itemproperty "HKLM:\\SOFTWARE\Microsoft\Windows NT\CurrentVersion").digitalproductid[0x34..0x42] 
 # Convert in Hexa to show you the Raw Key 
 $hexa = "" 
 $value | foreach { 
 $hexa = $_.ToString("X2") + $hexa 
 "Raw Key Big Endian: $hexa" 
 # find the Product Key 
 $ProductKey = "" 
 for ($i = 24; $i -ge 0; $i--) { 
  $r = 0 
  for ($j = 14; $j -ge 0; $j--) { 
  $r = ($r * 256) -bxor $value[$j] 
  $value[$j] = [math]::Floor([double]($r/24)) 
  $r = $r % 24 
  $ProductKey = $map[$r] + $ProductKey 
  if (($i % 5) -eq 0 -and $i -ne 0) { 
  $ProductKey = "-" + $ProductKey 
 "Product Key: $ProductKey"

Step 2: Now you’ll need to re-enter the product key you determined in Step 1.

cscript slmgr.vbs -ipk productKey

Step 3: Finally, you’ll need to “Validate Windows” by:

  1. Select the Start button, right-click Computer, select Properties, and then select Activate Windows now.
  2. If Windows detects an Internet connection, select Activate Windows online now. You might be asked for an admin password or to confirm your choice.