its not that impossible
.. sheesh, said individual could be infected with a virus , made for remotely controling somebodys computer , in which case full access...
bad stuff. but, if your nickname changes on you like that
i'd wipe your computer clean
or, a script is installed on the persons system using plus!, that gives them kinda like secret access to type commands & be able to do that to you, in which case.. get rid of any weird scripts not posted on this forum or in the download section.