My Lenovo Yoga 500 won't wake up?

Hello i'm the happy owner of a lenovo yoga 500 and i have put it in sleep mode for a while now and now it won't wake up so i can't turn it on. I have lernt my lesson, no more sleep mode… But how do i get it to wake up?

Long hold on the power button? Like 30 seconds or more…

Curious… How long has " sleep mode " be on? Reason… Sleep mode requires power from the batteries…( hello )…