Hello, my Lenovo y500 laptop has not been working properly after normal shutdown (with fast boot on win8.1 enabled). After plugging AC adapter, laptop turned on by itself (I didn't press power button) but nothing appears on the screen - I hear quite loud fan from inside. So the screen is black, it doesn't even show 'Lenovo' logo. What's more, I can't even turn the laptop off by hitting power button! I can only do that by unplugging AC... Did someone experience such things?