Drivers do Bootcamp no Windows 8.1

Ola, tenho um imac 21'' (mid 2011) com bootcamp e windows 8.1 instalado. Recentemente a tecla fn to teclado e o scroll do magic mouse pararam de funcionar. Baixei os drivers do bootcamp através do utilitario de Bootcamp mas no momento da instalacao o windows informa que os drivers instalados são mais novos dos que estou tentando instalar. O teclado e magic mouse funcionam normalmente no OS X. A camera integrada tambem não está sendo reconhecida.

Hi, i have an imac 21" (mid 2011) with bootcamp and windows 8.1. Recently my keys from the keybord that change de brightness and the volume stopped working, the scroll from the magic mouse also don't work. I've tried to download the drivers from Bootcamp Utility but when i try to install windows says there are better drivers installed and won't let me update them. The keyboard and mouse are working well on OS X. Facetime built-in camera also don't work.