After a control panel fix Office 2013 requires a key i no longer have

HI there
I had my computer checked and upgraded ready to begin study and they installed Windows 10.
When I went to use it no Office applications worked.
As I could not keep anything open to go to "file" I searched internet and followed directions for a repair via the control panel (internet repair).
It took ages and must have reinstalled the whole program as now when I open Office 2013 home and student version it asks for a product key or my account.
HOWEVER I cannot find the product key any more after many house moves AND when I log in to Microsoft it says my account is not linked to this product.
I tried instructions from internet for a ?dry boot ? using msconfig .. which made no difference .. and now not sure if everything from that is back where it should be.
I also logged onto Microsoft and booked a tech call but 24 hours later have not received one.
Please help. I am at my wits end.

Hi Melsin, I have seen a similar situation to one you are describing. The product key should be able to be found by running 'belarc advisor'. Try and log in to your Microsoft account and de-activate the previously installed version in My Account>My Installs. Also ensure that you have installed the 32bit option. If this fails Microsoft Technical Support should be able to deregister and run a few commands using an elevated CMD Prompt, but check these options first.

Hi Melsin, I have seen a similar situation to one you are describing. The product key should be able to be found by running 'belarc advisor'. Try and log in to your Microsoft account and de-activate the previously installed version in My Account>My Installs. Also ensure that you have installed the 32bit option. If this fails Microsoft Technical Support should be able to deregister and run a few commands using an elevated CMD Prompt, but check these options first. Also one more is https://diagnostics.outlook.com/#/