How do i find the product key of Windows 10 (OEM Sticker Erased)

I have upgraded from windows 7. MY OEM sticker has been Erased. I want save my Product key of windows 10. I am going to clean install it. what is command or Gui method to find the Product which is already installed.

Answer

There are two ways:

First Method:

1. Download Produkey utility tool from nirsoft (http://www.nirsoft.net/utils/produkey-x64.zip)


2. Run ProductKey.exe.

You'll be able to find product key.

Second method:

1. 
   

   Open 'Run' (Press Windows key + R)

   
   


2. 
   

   Type: slui.exe 4 then hit Enter

   
   


3. Select your country from the list menu


4. choose the option phone activation, then wait for an agent to assist you.