From what I can find online, Myerson was put into his position in July 2013, Nadella into his in February 2014, so it's entirely possible that it was actually Myerson doing these things on his own and it just happened to collide with Nadella's promotion, but I would also assume that a Steve Ballmer would have told Myerson off by now, at the very least for the malware-like upgrade strategy, whereas it seems like Nadella is entirely ok with it, heck from how much the man has said to it, you could assume he doesn't even know that it's happening.
Also, at a company like MS, I think its a naive to think the big decisions in regards to Win10 have zero input from the CEO level. Also the CEO is responsible for the calls of the higher ups. Even if Nadella is hands off with Windows, the fact that he isn't intervening is a sign of incompetence.
I don't know why people persist in thinking the CEO is just a ceremonial role in big companies.
Satya Nadella is the CEO of Microsoft.
Terry Myerson is the Executive VP in charge of the Windows division at Microsoft and is the one calling the shots with respect to Windows.
I don't know why people persist in thinking that CEOs are directly responsible for every decision a company makes, particularly at huge companies.