Certainly OS X vs. Win is endlessly debatable. I agree with Carl that,
unless she's already acclimated to the Apple environment, there's less of a
learning curve in going from XP to Win 7 (probably even to Win 10) than in
going to OS X.
But here's a new thought: why not fix her XP software? If all the ports
have failed (yet work as hardware, proven by your test) there must be some
one point of failure. Some Googling would probably turn up the problem.
In fact, have you tried running:
sfc /scannow
-- that alone could completely solve the port problem (ever the optimist, I
am).
Regards,
Harry