I recently gave my niece my old laptop…..

I recently gave my niece my old laptop and all of the login information was the same as my hotmail account (not the one I used to set this up). I tried to login this morning and it says my account does not exist. Since I have been using this account since the early 90's I know this is not true. I also logged in on Friday evening, so it shouldn't be showing inactive. I really need to be able to access this account because I have business emails in it (I hope). Is it possible when she changed things to her needs that she may have reset the password or (God forbid) deleted the account? Please help!