7. Status lights, blinking light codes, troubleshooting lights, and POST error messages
Carefully observe any behavior the computer may be exhibiting: status lights, blinking lights, and POST error
messages during boot. It is important to understand what these indicators mean.
Status lights
See the chapter titled “External Component Identication” for light locations. The following table describes basic
lights on the computer.
Component Description
Power button When the computer is o, press the button to turn on the computer.
When the computer is on, press the button briey to initiate Sleep (Windows) or Suspend
(Linux).
When the computer is in the Sleep state, press the button briey to exit Sleep (Windows) or
Suspend (Linux).
When the computer is in Hibernation, press the button briey to exit Hibernation.
CAUTION: Pressing and holding down the power button results in the loss of unsaved
information.
If the computer has stopped responding and operating system shutdown procedures are
ineective, press and hold the power button.
AC adapter and battery light White: The computer is connected to external power and the battery is charged from 90 to 99
percent.
Amber: The computer is connected to external power and the battery is charged from 0 to 90
percent.
Blinking amber: A battery that is the only available power source has reached a low battery
level. When the battery reaches a critical battery level, the battery light begins blinking rapidly.
By default, the critical battery level is dened in Power Options as 5%.
O: The battery is fully charged.
68 Chapter 6 Troubleshooting guide