How to identify LED Light codes:

When a laptop or computer first powers on, it goes through an initial set of diagnostic tests to make sure vital components are preforming correctly. These tests are called POST or Power On Self Test. When a test fails, the user is notified via POST codes, Light codes, or Beep codes. For diagnosing LED light codes you need to:

• Power on the laptop or restart it if it is already on.
• Identify the correct flashing light sequence.

Dell Inspiron 1420 LED Light Codes
LED Light Code	Component Causing No POST	Possible Solution(s)
	Motherboard / System Board Fault	Replace the motherboard / system board.
	RAM Memory Fault	Reseat the memory sticks. Replace the memory sticks. Replace the motherboard / system board.
	CPU Processor Fault	Reseat the CPU. Replace the CPU. Replace the motherboard / system board.
	RAM Not Detected	Install the memory sticks. Reseat the memory sticks. Replace the memory sticks. Replace the motherboard / system board.
	Keyboard Fault	Reseat the keyboard cable. Replace the keyboard. Replace the motherboard / system board.
	Video Card Fault	Replace the video card. Replace the motherboard / system board.
	USB Controller Fault	Unplug the USB devices. Replace the motherboard / system board.
	LCD Screen Fault	Reseat the LCD cable. Replace the LCD screen. Replace the motherboard / system board.