I have a Late 2014 Retina iMac with wireless keyboard. I had been running Windows 8 via Boot Camp but recently decided to downgrade to Win 7 Home Premium x64. I can't for the life of me get the Function keys to adjust brightness and volume working under Win7. Things I have tried: - Downloaded the support files through Boot Camp Assistant onto a USB key. This includes trying each of the three steps in BCA one at a time as recommended in another thread. Installed Windows as per the proper instructions. - Boot Camp Control Panel is loaded under Windows. From within BCCP I can alter the attributes of my Apple wireless trackpad. Selecting the Fn key options does absolutely nothing, pressing [FN]+[F11] or just [F11] with either setting only ever activates [F11] not volume control. - Tried installing the keyboard driver direct off the USB key. It comes up with the error 'Cannot Complete the Device Driver Installation Wizard. The device driver installation wizard was unable to find any drivers designed for your machine.'