Why my computer turn on the switch light is not showing

[vencheng Woo]

Several days ago, while my computer is at sleeping condition, but hardware yellow switch light is't showing, so I hit the switch,it caused computer shout down, I restart computer, then I found the green light is not showing too, but side yellow light is blinking, what is the problem? and how to repair?
My computer is still working in very good condition.

 

[Cyberat_88]

Is the battery ok ? Try removing battery and work off the power supply, do the lights show proper then ?