Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.
I am sorry to know that you are facing problem with your Lenovo Yoga 900.
Just to let you know its a brand new laptop and its covered under warranty and you are eligible to get a free replacement after troubleshooting if found a hardware fault.
Steps to follow and let me know how it goes.
Unplug the Ac adapter and then press and hold down the power button on the laptop for 30 seconds make sure Ac adapter is not connected while performing this step.
Release the power button after 30 seconds and then reconnect the ac adapter power it back on and keep tapping the F8 key few times when you power on.
let me know how it goes.