Open Command Prompt as administrator
Type `wmic path softwarelicensingservice get OA3xOriginalProductKey`
Press Enter
Check the displayed product key
Open PowerShell as administrator
Type `(Get-WmiObject -query ‘select * from SoftwareLicensingService’).OA3xOriginalProductKey`
Press Enter
Check the displayed product key
Open Registry Editor
Go to `HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionSoftwareProtectionPlatform`
Look for `BackupProductKeyDefault`
Check the product key value
Use a third-party key finder tool if needed
Check the Windows sticker or packaging if your PC came with one