Find your Windows product key with ShowKeyPlus.
Applies to Windows 7, 8 and 10
- If you purchased Windows from an authorized retailer, the product key will only show as the Installed key. This applies to OEM System Builder keys as well.
- If you purchased a new PC running Windows, the product key will be included in the firmware in the case of Windows 8 or 10 - or as an OEM marker, in the case of Windows Vista or Windows 7
- Apart from the key, the associated Edition of each key is displayed below it.

• Should you have a backup which includes a Windows folder, the key from that installation (as well as the
previously installed key, if that installation was an upgrade), can be retrieved using the Retrieve key from backup link.

• In order to verify the edition your key is associated with, use the Check product key link to confirm.

- Hint: Click/tap ‘Version’ link to toggle between light and dark modes. NB Dark mode will not be saved as it supports Windows high contrast - it will adjust to the underlying system scheme if so selected ( Thanx Cliff S )

Download: ShowKeyPlus
ShowKeyPlus Awards
Findmysoft has rated ShowKeyPlus 5 out of 5 stars, naming it Essential
Link

Note
The current version includes a routine that checks GitHub for newer versions. Some Anti-Malware applications may flag it as PUP. It's a false positive.
AV's that have not white-listed it, may require that you create an exception in their settings.
Virustotal results
Code:
Version history:
Update Version 1.0.6371
Bug fix:
- Background opacity on messagebox pop-up
Update
Version 1.0.6320
Bug fix:
- Suppress messagebox when in CLI mode
New in this release:
- Added key checking support for new editions in Creators Update: Windows EnterpriseG and Windows Cloud
Update
Version 1.0.6125
Bugfix:
- Version check returning null error
System.NullReferenceException: Object reference not set to an instance of an object.
at ShowKey.frmKeyInfo.bgwVersion_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e
- Product key checking referencing incorrect dll. on Windows 32-bit versions
NB: Windows 7 32-bit still does not support key checking of Windows 8 nor Windows 10 keys.
It will report those keys as Invalid, but they should be checked on Win 7 64-bit or any Windows 8 or Windows 10 version.
New in this release:
- Exception wording added for valid keys with invalid configuration resulting in a null response for edition.
- Cosmetic fixes.
Update
Version 1.0.6084
New in this release:
- Retrieve Windows 8 and Windows 10 key editions on Windows 7 installations.
- Use CLI to generate a text file of installed, original and OEM key(s) and their editions, silently.
Usage:
"[path]\ShowKeyPlus.exe" "[path][filename].txt" (or any text compatible extension, eg: .doc, .csv etc)
- Implemented Accent colour as the base scheme.
- Background changes to opaque when pop-up visible.
Update
Version 1.0.5835
Bug fix:
- Some motherboards (eg. Gigabyte) have a pre-installed MSDM table in the firmware without an OEM key embedded. Exception caught if key not present.
New in this release:
- Additional DPI scaling compatibility.
Update
Version 1.0.5815
Bug-fix:
- Forward-navigation arrow displaying incorrectly.
- Check version dialog was not returning to calling thread.
- Windows 8 reporting duplicate installations.
Update 01-Dec-2015:
Version 1.0.5812
New in this release:
- Automated discovery of pre-existing Windows installations (from Windows and Windows.old folders)
- Last used theme gets saved for use the next time the application is launched.
- Some GUI enhancements for DPI scaling.
- Included a version check to alert of new releases
Update 09-Sept-2015:
Version 1.0.5730
New in this release:
- Improved threading and exception handling modifications.
- Changed to a modern user interface.
Update 30-June-2015:
Included non-native support for Window 8 and Windows 7 key checking (as the former has been removed from Windows 10.)
NB: Windows 7 key checking is slow due to it having quite an extensive range.
Update 08-June-2015:
Bug fix - Windows Vista/7 marker was returned from the MSDM rather than SLIC table.
Update 07-June-2015:
Added Windows 7 support. SLIC and edition.
Update 19-May-2015:
Minor bug-fixes
GUI improvements.
Update 16-Apr-2015:
Added Product key checker
Update 15-Apr-2015:
Added ability to retrieve key from backed-up windows image.
This requires redirection to the offline \Windows\System32\config\SOFTWARE hive - it has no file extension.
Update 17-Mar-2015:
Added OEM edition retrieval.
Original key and edition only appears after an upgrade (eg. Pro to WMC)
**************************************************************************************************** ************
Key types:
OEM: DM = PC specific keys found embedded in the Microsoft Data Management (MSDM) table of the firmware of Windows 8 and Windows 10 factory installed PC's.
OEM: SLP = System Locked Pre-installation key - Win Vista/7 manufacturer specific keys used to mass activate those installations. Activation is off-line with a SLIC table in the firmware and matching Certificate installed together with the key.
OEM: COA = Certficate of Authenticity key found as a sticker attached to PC's factory installed with the above OEM:SLP method as a backup for on-line re-activation.
OEM: NONSLP = Non-System Locked Pre-installation key a.k.a System Builder keys - available from re-sellers and acts as retail on-line activation keys but with an OEM EULA.
Retail = Full Packaged Product (FPP) keys, available from a retail merchant or Microsoft on-line (NB: Windows 10 purchases from Microsoft Store are digital entitlement licences and use a generic key for installation.)
Volume: MAK = Multiple Activation Key is a single key used to on-line activate a pre-determined number of Windows installations.
Volume: GVLK = Group Volume License Key, is a generic key for editions of volume licence versions that activate off-line via a KMS server.
WAU = Windows Anytime Upgrade - Retail key that comes at a reduced price to be used to upgrade an activated previous version of Windows.
**************************************************************************************************** ***************

Note
Should your key display as BBBBB-BBBBB-BBBBB-BBBBB-BBBBB, it is a placeholder Windows inserts after activating a MAK key.
The reason being, these keys can have thousands of activations (for which companies pay huge amounts) and should someone steal one, they could sell that same key to thousands and each will activate as if part of a company network - it's thus a security feature specific to MAK's.
**************************************************************************************************** ****************
PS: Please see here regarding unblocking the .exe