Dell Inspiron 8100 - Manual (Page 55)

l To decrease the volume, press the <Fn> and the <Page Dn> keys.
l To enable or disable (mute) the integrated stereo speakers or external speakers, press both of the volume control buttons simultaneously.
When you mute music, the computer may take a moment to respond.
Dell™ AccessDirect™ Buttons
You can also reprogram the button scheme to control CD or DVD player functions.
Left Side View
Security Cable Slot
HINT: If no sound comes from the speakers, press <Fn> and <End> and check the volume control buttons to make sure that the sound is not disabled.
HINT: To launch the Dell Solution Center, the computer must be turned on and functioning properly.
1 Press this button to launch the Dell Solution Center, where you can find support and educational tools that Dell has installed on your computer.
2 Press this button to launch your default Internet browser.
3 Press this button to launch http://www.dell.com, or reprogram the button to launch a program of your choice.
4 Press this button to open your default e-mail program, or reprogram the button to launch a program of your choice.