HP ProBook 4540s power button keeps blinking

Hello,
When I tries to turn on my laptop, the power button keeps blinking once every 5 secs. when it stops, the charging LED blink and this light stops when the power button blink (They continue each other). During the blinking of the power button, the Harddisk LED blinks 1 red and 1 white light. I dunno what may cause such problem, i suddenly happened.

The following video is when the battery is connected to a charger. The blinking sequence changes when it is on a charger.