When my PC starts each light momentarily flashes to indicate each respective component is operating correctly, if something was wrong they would remain lit. There is also a light to confirm the board has power I believe but I do not specifically recall when it turns off. If you aren't experiencing any problems with the computer you are good to go.
Currently I m not receiving any problems. I loaded defaults on my bios after the lights were off.. I guess it's the mobo power led that is always on..it's in yellow..rest are off..