Most of what I've seen listed here would not work for a kid. 1) If I were a kid and someone put software on my computer that was annoying I'd just uninstall it. Password or not it's not like it's hard to remove this stuff - at most you'd have to boot to safe mode and do it through there. 2) The basis of a lot of what I'm seeing is that changes won't be permanent... uhhhhh the kid will just make them permanent. He trusts that pirated game crack more than security software. Focus on security that stays away from the kid. Nothing they'll have to interact with. EMET and Chrome or IE9 to deal with exploits without being a pain to deal with and pretty much any AV will cover the rest, I'd go with MSE because of its consistently low false positives. Anything more than that and they're just going to ignore the security.