Hi,
I had the same problem until 5 min back in time. I found in the manual of my Aspire 5100 that you there is the option "AcerClearVision" in the software "AcerArcade". See manual:"Acer Clear Vision is a video enhancement technology that detects video content and dynamically adjusts the brightness/contrast/saturation levels so that you do not need to change the color settings if the movie you are watching contains scenes that are overly dark or too bright."
So i opened "AcerArcade". There you take: "movie or cinema--> settings -->display settings" en there you change in the option 'color profile' 'ClearVision' to 'Original'.
In my case the problem is solved; the laptop is pluged in and my brightness level stays on 100% (even when it becomes dark in the room!!).
Kind regards,
John Sony
John Sony
August 2008