Asus P7P55D-E LX - Manual (Page 40)

1-28 Chapter 1: Product introduction
1.11.3 Onboard LEDs
1. POST State LED
POST State LED checks DRAM during motherboard booting process. If an error
is found , the LED next to the error device will continue lighting until the problem is
solved. This user-friendly design provides an intuitive way to locate the root problem
within seconds.
You may disable the POST State LEDs in BIOS. Refer to section Boot Settings
Configuration for details.
2. Standby power LED
The motherboard comes with a standby power LED that lights up to indicate that the
system is ON, in sleep mode, or in soft-off mode. This is a reminder that you should
shut down the system and unplug the power cable before removing or plugging in any
motherboard component. The illustration below shows the location of the onboard LED.