Password problem. Mine works fine on my PC and my wife who has a different address has password rej

My address and password works fine. My wifes different address and password works fine on her existing laptop.  But, she is changing her laptop and when I checked logging in with what I believed is her password it is rejected  I need the existing or a new pssword  as she takes delivery of a new laptop next week.  I tried resetting her password via her address but that address gets rejected.  Any thoughts how I find the old password or reset it to a new one.  Thanks  MrBear