lenovo suddenly shuts down

[BlackHana]

so i was using my lenovo z400 and suddenly it shuts down by itself. When i tried to turn it back on, it won't start up, any help?

 

[boosted1g]

Please elaborate wont "wont start up" means.

Press power button and nothing?
Press power button and lights come on and turns back off?
Lights stay on but blank screen?
Post screen comes on and then loops
Post screen then starting windows screen and loops?