I use two monitors which are connected to my Y560 for listening/watching a show when working at the other monitor.
The screen brightness always auto adjust to the lowest setting no matter how many times I change the setting.
I have checked for updated drivers and nothing. I have no other programme running in the background. What is even more odd, though it may be a coincidence, is that my Sony Bravia is now auto adjusting its brightness but erratically which seemed to have occurred after connecting it to the laptop HDMI port.
It is because of the setting in Lenovo OneKey Theatre application. Set it to Normal mode will do.
In addition to both applications of Lenovo Energy Management and ATI Catalyst, there is actually a Theatre button just below the screen on the right that overrides everything else when it is set to INTELLIGENT mode.
Once it senses audio or a video is playing, it reduces the brightness regardless of whether you have increased the brightness volume or not.