Compaq Armada 7800 Reference Manual page 153

Some software applications, such as game programs, include their
own volume controls. You may need to adjust the volume controls
to get the desired sound levels.
The volume control on the computer overrides all other volume
controls in the software. That is, the volume from the integrated
stereo speakers, external speakers, or headphones will never be
louder than the sound level selected using the computer volume
control.
Using Audio Features 10-9