You might need your product key to speak with a Microsoft representative to resolve certain issues with your product license and might have lost this key. Microsoft writes your key into its registry, keeping record and using it for Windows Update. To operate within this registry, you need to use Microsoft's Registry Editor, a program included in the Microsoft Windows Program Suite.
Instructions
1.
Press the Windows logo key + R.
2.
Type "regedit" in the text box and click "OK."
3.
Navigate to the following path using the left side of the registry editor window: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion.
4.
Look under "ProductID" in the right side of your window. This represents your computer's product key.
