I play games with high brightness settings, higher than the games themselves allow, so I used to change this through Nvidia Control Panel (Gamma & Brightness sliders). But now this doesn't work anymore, which means I can't play certain dark games (eg Doom 3) anymore.
It used to work but now maxing out the sliders doesn't do anything anymore, not in games or on the desktop.
I have a 7800GS (Agp) with the 178.24 drivers on XP SP2 (Amd A64 3200+, 2Gb Ram).
My monitor's brightness is already all the way up.
I maxed out the settings, then started Doom 3 and ingame all was dark.
But when I alt-tabbed, the icons of active programs were all bright like they should be. Then I quit the game and the desktop and the alt-tabbed icons were back to normal.
I'm not too keen on upgrading drivers, I'll use it as a last resort attempt.