Hp pavillion 15 laptop not booting but has power.

Last night when I switched on the laptop, it wouldn't start - the power was on, the wifi light was on but no boot up. I pressed the power button again to restart it and after a while it came on. It worked fine. This morning it booted up ok and ran windows update. After the updates it asked to be restarted, so ok, I restarted it. It shut down and did the updates, but never restarted. Now when I press on, the thing has power but doesn't go beyond a black screen.

Any advice? It's only four months old and hardly used as I prefer my tablet!

Any suggestions will be gratefully received.

Thanks.