Make sure your laptop has the lid down and it is connected to the mains.
Take out the power lead at the laptop connection for a second or two.
Put it back in again.
Then immediately [but carefully] lift up the lid of the laptop and then immediatly press the power-on button on your laptop.
If all goes to plan, it might spark into life again.
[Had a similar problem with my HP laptop and the above procedure got it goin' again!]