I have a Gateway laptop that originally came with Vista, and I upgraded to Vista Ultimate. I have always been able to change the brightness settings by using Func+Up or Func+Down but a few days ago it stopped working and is always at MAX bright!

Anybody knows why is that happening and how to fix it? It is very annoying not being able to dim the screen when in battery mode, since it can make quite a difference in battery life.

Thanks!
['https://superuser.com/questions/95202', 'https://superuser.com', 'https://superuser.com/users/15180/']
The screen brightness can be changed in the power options section of Control Panel (or by clicking the little battery icon in the system tray, though i'm unsure if that's new to Win 7 or works in vista).

As for the Fn keys stopping working, it's likely that there will be an app you can install from the Gateway website for your machine that will re-enable them. I've had this issue before too (though not on a Gateway), and had to reinstall the program from my manufacturers website to get proper Fn key functionality back.
Ensure you have the latest video driver, downloaded from the website of the card's manufacturer.

If you have installed "Dox Optimised Forceware", then uninstall it first.