The most popular way of retrieving Windows product key is to use a third-party software. While there are plenty of free apps and software available for this job, the fact is that you can recover Windows product key from the registry without using third-party software.
1. Copy and paste the followind script into a Notepad on your desktop or copy and paste the script from Microsoft Technet website. Save it on your desktop as RecoverKey.ps1. Note: is important to save the file as a .ps1 extension.
2. Open Windows PowerShell as administrator. To do this, in Windows 8 (8.1), Metro UI Search for Windows Power shell it will show up on the left pain or immediately under the search.
3. Right click it and run as Administrator.
4. Click on the Yes button if prompted with the User Account Control (UAC) dialog.
5. In the PowerShell window, type the following command (or copy and paste it from here ) and press Enter key to change the execution policy for non-signed scripts.
6. Enter ‘Y’ key when you see “Do you want to change the execution policy” message.
7. Finally, type the following command and press Enter key to view your Windows product key.
Import-Module C:\Users\AvoidErrors\Desktop\RecoverKey.ps1; Get-WindowsKey
In the above command, replace “C:\Users\AvoidErrors\Desktop\RecoverKey.ps1” with the path to the previously saved RecoverKey.ps1 file. To easily get the path, press and hold down the Shift key, right-click on RecoverKey.ps1 file, and then click Copy as path option from the context menu.
If the above script didnt work is because there is some text processing on this site that occurs during a post and re-formats various characters such as quotes and hyphens. The result is incorrect formatting of the script that has to be corrected manually or you can copy and paste the script from Microsoft Technet website.