Unable to change display brightness

I just got an acer one 8.9 (AOA150)
I am unable to get the screen brightness to change
I turn to this forum as a last resort, before i return this thing and get a different brand (as this is my second acer one with problems)
It seemed to work fine for the first hour or so, the screen would brighten when plugged into an ac adapter, and dim when on battery. I never got a chance to try the fn keys but i am pretty sure they worked fine,
I noticed my screen dim at one point, while I was simply browsing the web.
Since this moment my screen has been stuck on what is probably its lowest setting.
The FN keys, power settings and ac vs battery has no effect at all on screen brightness.
I can't get it to budge.
I have gone so far as to install a fresh copy of windows, this time vista rather than xp. Stil no luck.
I have installed all the drivers and everything else seems to be working great, but the display is so dark that using it gives me headaches.
Under device manager, monitor says "generic pnp" . Im not sure if thats what it should say, or if im missing a driver that I cant find for the life of me.
I really hope someone can help me. I really like my acer, but its unusable like this.

 

I'm having a similar problem on a brand new aspire one. The screen is appallingly dim, the fn-arrow keys move a slider but there's no visible result.
I wasn't overly concerned because I was replacing windows with linux, but I'm receiving exactly the same behavior on a different OS.
Makes me think hardware.

If anyone has had a similar experience I'd love to hear what you did.

 

same problem here, I'm under an AO531h
I bought this one for its long battery duration and now I cant switch brightness.

 

Anybody get an answer to this? I replaced a broken screen with an LG bought on eBay and it works, but is stuck on very dim. It's like the backlight is off. The backlight "works" though. When I first turn it on it's super bright, even from the back, but as soon as it starts actually booting up it goes dim. The Fn keys do nothing, not even bring up a slider. The broken screen was not this dim, but I don't recall if the Fn keys worked then or not to be honest.