Thanks !
Installed default options and clearly EVR custom was selected (by default) during the setup but after installing, the MPC options -> playback -> Output was set to Overlay Mixer
Checked MPC menu -> View -> Renderer Settings -> Presentation -> "Disable desktop composition" was unchecked by default.
Anyway, now changed to EVR custom and Windows 7 Aero effects is NOT broken when playing a flv video.
