When i try to power. when i try to power up my laptop i have to press the power button 3 times

Question

when i try to power up my laptop i have to press the power button 3 times before it comes on and it stays on for about 3sec. then shuts down.
i have tried it with the battery and the AC plug but it still does the same thing.
i hear the cdrom run within that 3sec. then it shuts down.