How to Find Your Lost Windows or Office Product Keys

Key Takeaways

The best way to recover a lost product key for Windows or an Office program is to use a third-party program, like Nirsoft’s Produkey or ShowKeyPlus. You may also have a sticker attached to your PC or disk box with a product key written on it.

If you’re planning on doing a reinstall of Windows but can’t find your product key, you’re in luck because it’s stored in the Windows Registry. It’s just not easy to find, and it’s impossible to read without some help. Luckily, we’re here to help.

Where Is Your Windows Product Key Stored in the Registry?

The Windows Product Key is hidden in the registry.

As you can see in the screenshot above, the product key is stored in the registry but is in a binary format that can’t be read by humans unless you are some sort of Cylon. You aren’t, are you?

We’re not really sure why Microsoft went to great lengths to make it difficult to see the product keys for their software, especially since they are stored right in there in the registry and can be read by software, if not by humans. We can only assume that they don’t want anybody to re-use a key from an old computer.

The great thing is that you can even recover a key, even from a computer that won’t boot anymore. All you need is access to the disk drive from a working computer. Keep reading for more.

Where Can You Find Your Windows Product Key? The prompt to enter your Windows license key.

The key you need will be in one of three places:

  • Stored in software on your PC: When you (or your PC manufacturer) installs Windows, Windows stores its product key in the registry. You can extract this product key, and — often — enter it when reinstalling Windows on your PC. Crucially, you’ll need to grab it from your operating system before you begin reinstalling Windows or it could be deleted if you format your hard drive.
  • Printed on a sticker: Some PCs use a technology called “System Locked Pre-installation,” or SLP. If your PC uses this, the product key on your PC — the one stored in the registry, and the one key-viewer applications display — will be different from the actual key your PC needs. The actual key is on a certificate of authenticity (COA) sticker on your PC or its power supply. The one in the registry and key-viewer application is a red herring. This system was common for Windows 7 PCs.
  • Embedded in your PC’s UEFI firmware: Many newer PCs that come with Windows 8, Windows 10, or Windows 11 use a new method. The key for the version of Windows the PC comes with is stored in the computer’s UEFI firmware or BIOS. You don’t even need to know it —assuming you’re installing the same edition of Windows the PC came with, it should automatically activate and work without you needing to enter a key. It’ll all happen automatically.

Be sure to use the same version and edition of Windows the computer came with. In other words, if it came with Windows 11 Home Premium, you can’t install Windows 11 Professional.

Find Product Key Stored in the UEFI on Windows 10 or Windows 11A Windows laptop manufactured by Acer.

Let’s start with the simplest situation. On newer Windows 10 and Windows 11 computers, the key isn’t stored in software where it can be wiped, or on a sticker where it could be smudged off or removed. No one can glance at your computer’s sticker to steal its product key. Instead, the key is stored in the computer’s UEFI firmware or BIOS by the manufacturer.

You don’t have to do anything special if you have this. You should just be able to reinstall the same edition of Windows the PC came with and it should just work without even asking you for a key. (Still, it may be best to find the product key using one of the below methods and write it down before reinstalling Windows — just in case.)

If you want to find the UEFI-embedded key and write it down, you can do so quite simply. Just open the Start menu, type “powershell” into the search bar, and run the Powershell application that comes up.

Open the Start Menu, search

Then, enter the following command and press Enter:

(Get-WmiObject -query 'select * from SoftwareLicensingService').OA3xOriginalProductKey

You should be rewarded with your embedded license key. Write it down and store it in a safe place.

We obfuscated our product key with a green box. You’ll see something like: A23BC-GHN23-NBK32-VNS98-JKLOL

The Windows 11 product key is hidden under a green block.

Use NirSoft’s ProduKey to Find Windows 10 or Windows 11 Product Key

Nirsoft’s ProduKey will almost definitely set off your antivirus because of what it does and how it works. It is not malware, however. ShowKeyPlus is an option if you want a solution that works for Windows 10 and Windows 11 that won’t set off your antivirus.

The easiest way to get access to your product key is with a third-party utility, and there’s nobody better at those than NirSoft. Their utilities are always crapware-free, and are always really useful. The only issue with this particular utility is that some antivirus will detect it as a false positive, because some malware might try to steal your product key.

All you have to do is download ProduKey, unzip it, and then run it to immediately see all of your product keys. It’s as simple as that.

The product key from a Windows 10 PC.

If you want to recover a key from a dead computer, you can hook up the hard drive to a working PC, and then run ProduKey and use File > Select Source to point to the external Windows directory. You can then grab the keys from that computer easily.

Go to File > Select source on NirSoft's ProduKey.

You can also use a Linux live CD to pull the Windows directory off the other computer and onto a thumb drive, or just grab the registry files if you prefer. If you need help, we’ve got a guide to pulling data off a dead computer.

Use ShowKeyPlus to Retrieve Product Key on Windows 10 or Windows 11

Nirsoft’s program works — but it might tigger a warning in your antivirus, or even your browser. If you don’t want to deal with that, ShowKeyPlus is a good alternative. ShowKeyPlus is available directly from the Microsoft Store for Windows 10 and Windows 11.

Open up the Microsoft Store, find ShowKeyPlus, then click the “Install” button and wait while it downloads and installs. It shouldn’t take very long; the program is pretty small.


Click “Open” after it has downloaded, and the product keys on your system will be displayed.

ShowKeyPlus might display multiple keys depending on what you've done with your system.

It is important to note that there might be both an installed key and an OEM key. OEM, or Original Equipment Manufacturer, keys are tied to the hardware of the device. If you’re using a prebuilt desktop PC or a laptop, the OEM key and the installed key will be the same unless you separately purchased a different Windows license.

If you did purchase and install a separate Windows license for a prebuilt or laptop (or for a computer you built yourself) make sure you grab the installed key, not the OEM key. OEM keys are subject to more restrictions than retail keys, so you don’t want to accidentally use the wrong one.

Use a Script to Recover Your Windows 10 or Windows 11 Product Key

If you don’t want to use a third-party utility to find your product key, you can always use a visual basic script (VBS).

Copy and paste the script below into Notepad. Then, go to File > Save As, set the file type to “All File,” then name the script something like “Product Key Script.vbs” and save it.

Saving the script with Notepad.

 Option Explicit
Dim objshell,path,DigitalID, Result
Set objshell = CreateObject("WScript.Shell")
'Set registry key path
Path = "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\"
'Registry key value
DigitalID = objshell.RegRead(Path & "DigitalProductId")
Dim ProductName,ProductID,ProductKey,ProductData
'Get ProductName, ProductID, ProductKey
ProductName = "Product Name: " & objshell.RegRead(Path & "ProductName")
ProductID = "Product ID: " & objshell.RegRead(Path & "ProductID")
ProductKey = "Installed Key: " & ConvertToKey(DigitalID)
ProductData = ProductName & vbNewLine & ProductID & vbNewLine & ProductKey
'Show messbox if save to a file
If vbYes = MsgBox(ProductData & vblf & vblf & "Save to a file?", vbYesNo + vbQuestion, "BackUp Windows Key Information") then
Save ProductData
End If
'Convert binary to chars
Function ConvertToKey(Key)
Const KeyOffset = 52
Dim isWin8, Maps, i, j, Current, KeyOutput, Last, keypart1, insert
'Check if OS is Windows 8
isWin8 = (Key(66) \ 6) And 1
Key(66) = (Key(66) And &HF7) Or ((isWin8 And 2) * 4)
i = 24
Current= 0
j = 14
Current = Current* 256
Current = Key(j + KeyOffset) + Current
Key(j + KeyOffset) = (Current \ 24)
Current=Current Mod 24
j = j -1
Loop While j >= 0
i = i -1
KeyOutput = Mid(Maps,Current+ 1, 1) & KeyOutput
Last = Current
Loop While i >= 0

If (isWin8 = 1) Then
keypart1 = Mid(KeyOutput, 2, Last)
insert = "N"
KeyOutput = Replace(KeyOutput, keypart1, keypart1 & insert, 2, 1, 0)
If Last = 0 Then KeyOutput = insert & KeyOutput
End If
ConvertToKey = Mid(KeyOutput, 1, 5) & "-" & Mid(KeyOutput, 6, 5) & "-" & Mid(KeyOutput, 11, 5) & "-" & Mid(KeyOutput, 16, 5) & "-" & Mid(KeyOutput, 21, 5)
End Function
'Save data to a file
Function Save(Data)
Dim fso, fName, txt,objshell,UserName
Set objshell = CreateObject("")
'Get current user name
UserName = objshell.ExpandEnvironmentStrings("%UserName%")
'Create a text file on desktop
fName = "C:\Users\" & UserName & "\Desktop\WindowsKeyInfo.txt"
Set fso = CreateObject("Scripting.FileSystemObject")
Set txt = fso.CreateTextFile(fName)
txt.Writeline Data
End Function

When you double-click the VBS script, you’ll get a small popup that displays your Windows product key. It also lets you save it as a text file, so you can reference it later.

The Window 10 product key is obfuscated by a green box.

Read the Product Key From the Certificate of Authenticity Sticker

If you have a Windows 7-era PC, there’s a good chance the PC’s key is a single key the manufacturer uses for all their PCs. Thanks to “System Locked Pre-installation,” you’re not allowed to use that key to install Windows. If you try, you’ll get error messages about the key being invalid.

To check, you’ll need to look for a certificate of authenticity sticker on your computer. The COA sticker verifies that the computer came with an authentic copy of Windows, and that sticker has a product key printed on it. You’ll need that product key to reinstall Windows — and, if the manufacturer used System Locked Pre-installation, that key is different from the one your PC came with in software.

Examine your computer to find the key. On a laptop, it may be on the bottom of the laptop. If your laptop has a removable battery, it may be under the battery. If there’s some sort of compartment you can open, it might be in there. It may even be stuck to the laptop’s charger brick. If it’s a desktop, look on the side of the desktop’s case. If it’s not there, check the top, back, bottom, and anywhere else it might be.

The bottom of a laptop showing a Windows 7 license key.

If the key has rubbed off of the sticker, there’s not much you can do. You can try contacting your computer’s manufacturer and explaining what happened, but we can’t guarantee they’ll help. Microsoft would always be happy to sell you another key, though!

The product key system is complicated to understand because Microsoft doesn’t really want typical Windows users to reinstall Windows on their PCs. Instead, they’d rather you use your computer manufacturer’s recovery media. But the recovery media is full of the bloatware you don’t want on your PC — that’s why so many geeks often opt to reinstall Windows on their new PCs.

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