An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
Hi,
Thanks for telling me what's going on. I get how annoying it is to not be able to get into your Microsoft Office stuff after a repair, especially when you can't remember which account you used. Usually, this happens because Office Home & Student is linked to your Microsoft account from when you first set it up. If you can't get into that account, the apps can't check if you have a valid license.
So, the best thing to do is try to get your Microsoft account back. Go to Microsoft Account Recovery and type in any email addresses or phone numbers you think you might have used. If you're not sure, look through your old emails for anything from Microsoft or Office that confirms you bought it. After you get your account back, just sign in again through any Office app or at office.com to get your license working again.
I hope this helps.
Best Regards,
Noel