Simple way to tell him he's wrong:
Windows is made by Microsoft.
XBOX is made by Microsoft.
XBOX support is built directly into Windows by Microsoft.
Ask him to call up Microsoft customer support to confirm these three truths.
If he refuses, he's the one who fucked up the computer, he's a lying sham of a father, and you should never trust him ever again, possibly to the point of considering cutting all ties.
Best and only acceptable answer in this thread.
Is it possible you had that horrifically adware-infested version of MotionJoy running?
Because if so, he was right.
But anyway, you should check this too, OP.