My name is ***** ***** GeekGirl :). Thank you very much for giving us an opportunity to help you. Please keep in mind as we work together that it often takes more several steps and/or answers to solve a problem. So If my answers don’t work or if you are not satisfied, please don’t Rate my answer as Bad or Poor Service, but please Reply back to me by clicking the “Continue Conversation” or “Reply” button and I will gladly continue to help. Remember, only Rate answer after you are 100% Satisfied. Please do not rate an answer, if you are not satisfied. If I am unable to solve your problem, I will open it up to our other experts in the hopes that someone else can help.
There are a couple of potential ways to resolve this issue. Was the computer running Windows 8.1 or Windows 7 prior to the upgrade? If it was running Windows 8.1 then you likely used a Microsoft account to login. I can defintiely help you with regaining access access to your microsoft account. What is the user name that you see on the welcome screen? Is it in the form of an email address? that is another good indication that it is a Microsoft accoutn password ***** can be reset.