Could not find another place to ask this question so I am horning in on the Windows 8 forum.  If you have no answer, I understand.   I have been searching for this and only  found partial answer.

I am giving an old computer to our son.   I  have cleaned out files I could delete.  I did a reset (keeping old files) to speed it up but not a restore to factory settings.  (This was originally a Windows 8 and has been upgraded)  The reset really worked and improved the speed dramatically.  

However, the sign in screen and password are MY gmail and MY password.  I tried a bunch of things to change that password but all i did was eventually change the password to a microsoft  one drive account. which leaves the  computer sign in screen unchanged.  Eventually I stumbled on Settings, Account, Sign in Options  and the advice to switch to a local user.  I was able to enter a new sign in name and password which now comes on when I turn on the computer and it works great.  

Question now is I would like to remove all traces of my email and password which I think are hiding under the administrative account somewhere.  I would like to change the email under that administrative account to my son’s and take out mine.  Can this be done?  Is this a fair question to ask you within the scope of this forum?  I would also hope to establish a Microsoft account for his email name which is linked to the computer.  Possible?