Skip entering the product key if you are prompted. If Windows 8.1 was already installed and activated, then its registered and will automatically activate when you reach the desktop and connect to the Internet.

If you are prompted to enter a key, use the following diagnostic key for the edition you have a license for to get the installation going.

Generic keys:

Windows 8.1 standard/non-Pro edition:

334NH-RXG76-64THK-C7CKG-D3VPT

Windows 8.1 Pro:

XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB

Forum helper

      Welcome : Read through this. Microsoft article and scroll down to

           "Locate your, windows product key for Windows 7 &  **8.1**"

Link : https://support.microsoft.com/en-us/windows/find-your-windows-product-key-aaa2bf69-

7b2b-9f13-f581-a806abf0a886#:~:text=Locate%20your%20product%20key%20for%20Wind****

Also, windows users find their - Product Key - using the

"Command Prompt as (Administrator)" others make use of

Third-party apps online, like : Product keyFinder, NeoSmart,.Etc

    To open "Command Prompt" just Right-click the **Start** button 

on the > Left screen corner > select - Command Prompt as (Admin)

 a small black Screen appears. Type the command below : After the **\_** Blinking dash

Wmic Path softwarelicensingservice get OA3xOriginalProductKey : **** press-Enter

After typed carefully the, above code : Cmd Prompt. will show the

activated product key : So you can write it down : Hope this helps,.?

Thanks - this was really helpful, but I did have two small problems with it:

1. When the script is copied and pasted as described here, it gets a couple of syntax errors (at least when copied from IE):
   • Some double-quotes are replaced by '?' (in addition, the double-quotes are not the basic ASCII / typewriter form, but come in left and right versions. I do not know if it mattered, but I replaced them all with simple non-directional double quotes ( " ).)
   • The '--' operator in the 'for' expressions is replaced by a single '-'.
2. You instruct the administrator to change (and probably weaken) the security policy, in order to load and run the script, but not to restore it afterwards, or to use Get-ExecutionPolicy to make note of what it was initially. If you do Set-ExecutionPolicy  RemoteSigned -scope Process, the change will apply only while the current shell process is running, and only within that shell.; see https://technet.microsoft.com/en-us/library/hh849812.aspx .)

This is the function definition - it may be easier to copy it accurately from here (note that the line beginning '$charsArray =' has been wrapped onto three lines in this post; however, when I tried copying it from this post, it pasted correctly as a single line.)

function Get-WindowsKey {

 ## function to retrieve the Windows Product Key from any PC

 ## by Jakob Bindslet (*** Email address is removed for privacy ***)

 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

 }

 }

If it helps as a ball park figure, the stats of my Windows Reinstallation Guide have about 25,000 clicks to Windows.Microsoft.com which is a slightly more accurate metric regarding the amount of people that have actually tried to follow the workaround to download the Windows 8.1 retail .iso. Subtract a little and divide by 2 so take the number to be 10,000. Say there are at least another 10 guides with similar metrics its a significant fraction of the Windows user base ~0.1 million. Taking your 1.8 million as the maximum size its about 5% of the userbase. Of course there are many users who got Windows 8.1 directly so this workaround would not apply. Moreover as mentioned the 8.x usage will likely contain many OEM licenses and I am not sure on the proportion of OEM to retail licenses. My guess its there would be a lot more OEM licenses as users get Windows 8 forced upon them when they buy a new PC and most users are quite happy on Windows 7. The fact that it doesn't work for OEM installs is a huge problem and one I've been trying to bring up with all my contacts within Dell for some time now. So taking into account only the Windows 8.0 → Windows 8.1 retail license the statistics should be a lot higher than 5 %. To a sense what I wrote is playing about with numbers but it is not a rare problem.