top three led light on a dell inspiron 5100 what do they mean

I have a dell inspiron 5100 there are three leds between the screen and the keyboard.   I know what the are in general however when the computer power button is pressed and the computer has a problem like no memory chip was detected or a video card problem or other problems these lights will give you information on what the problem is.  I know what some of the different combination mean however I would like to know what each combination of light mean. I have search for this information many times can anyone tell me what each combination of the three lights mean.