Hi, I accidentally reinstalled Windows 10 because of serious malfunctioning and obviously the serial number of student version is gone, I cannot find it anywhere else.

Email account that used to be registered at the very first purchase has recently been deleted so I also cannot find the serial number from the inbox; I might have received from the inbox. However, before the deletion, I made a new account with a new email address and the serial number before Windows re-installation.

I expected that I am of cause allowed to find the serial number that I put in once I made the new account at anytime but I was wrong, it doesn't even show up from admin menu. 

This issue has been asked and the support staff keeps saying that I have to provide the serial number that I am having no-serial number problem, even keeps answering my old questions I am getting exhausted. I just can't believe that I'm not able to find our the number that I put in as requirement through admin window.

Is there any route to find out the serial number with logging in? Thanks.