These settings don't always work with MC16.
My green button works perfectly to start Windows Media Center. However, if I configure MC16 to run Media Server at startup as Matt suggested, and also configured MC16 to disable Windows Media Center, the green button will still NOT start MC16. Pressing the green button basically has no effect - the pointer flashes to the "busy ring" for an instant, and then nothing.
This is with Win7x64.
If I uncheck the "disable windows media center" box, my green button still works to launch WMC.
So I feel your pain Pauly. I've never gotten the green button to launch MC16.