Dell Inspiron 4000 - Manual (Page 57)

The green lights located above the keyboard indicate the following:
l The light labeled turns on when you press to enable the numeric keypad.
l The light labeled turns on when you press to enable the uppercase letter function.
l The light labeled turns on when you press to enable the scroll lock function.
Keyboard
The keyboard includes a numeric keypad as well as the Microsoft® Windows® logo key that supports the Windows operating systems.
Track Stick
The track stick detects the pressure and movement of your finger for moving the cursor on the display and, along with the track stick buttons, provides full
mouse functionality.
Microphone
The internal microphone allows you to record voice audio.
Device Status Lights
The green lights next to the keyboard indicate the following:
l The light labeled turns on when the computer is turned on and blinks when the computer is in standby mode.
l The light labeled turns on when the computer reads data from or writes data to the hard drive.