Presario 1275 monitor controls under W2K

I upgraded a Presario 1275 to W2K to get a wireless card to work. Windows
found the correct display driver, and I manually installed drivers for the
Easy Access keyboard and Synaptic touchpad. Per Compaq, I set the monitor to
a standard 800x600 display. So far, so good.

All of the Fn keys work correctly except the monitor brightness and contrast
controls, and, presumably, the int/ext monitor button. Looking at the Easy
Access configuration, I see that:

The Standby mode button takes effect immediately.
Easy Access traps the CD player controls and implements them itself.
Easy Access traps the monitor controls, but simply reports they are not
programmable.
Easy Access lets me program the remaining buttons.

What exactly controls the monitor? I don't have any original CDs, so I don't
know if there is a utility these keys are trying to call, if the
functionality is built into the video adapter, or what. Any help would be
appreciated. A solution would be better!