Windows 10: Lost Windows 10 Product Key - MS PC Reset Failed

How do I get a product key or Windows 10 when this has been lost? I reset the PC as I am selling using windows reset and it failed. The failure corrupted my profile and windows would not start/allow me to login. I have no product key that I can find, I need a replacement. Product key not supplied when PC replaced by insurance many years ago. How do I get Microsoft to get me a replacement?

:)

 

How to recover lost Microsoft Office 2013 Product Key after Windows 10 Reset PC

Although the Windows Lost Product Key question has been asked before, this is slightly different.
I did 'Reset this PC' from Windows 10 Recovery without taking a backup of the system or files. All my files were safe but the Licensed Microsoft Office 2013 was removed. I have unfortunately misplaced the MS Office 2013 Student and Home product box. I have also checked with Windows Helpdesk if any of my emails are associated with the MS Office and the Microsoft Account; sadly, none are.

I read that that the 'Reset' cleans the registry and removes the apps. I am thinking of two ways to try and find the key

1. Use all the Free Key finders around then buy a paid one if they don't work
   
2. Use Recuva or a similar tool to try and recover the deleted old Windows Registry files
   

Has anyone faced a similar issue or can you think of an alternate way to try and get the Key?

 

Lost product key

I have lost product key of Windows 10 pro and MS Office after doing a factory reset. Is there any way to recover the same?

 

Windows 10 fails to update


When you finish testing the Avast suggestion, make sure that you restart your machine.

Then if the issue persists, please return to the trouble shooting list in post# 89

I think there are three steps that remain; the WU troubleshooter, reset WU components, and manual WU reset.