upd: Even better solution is to use the latest Windows 8.1 ISO which can downloaded using the following Microsoft’s tool. It instantly detects the video adapter and installs the required driver. http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media
This seems to be a standard problem for many Lenovo laptops: after Windows 8 enters sleeping mode, computer does not wake up - all the lights and fans are on, but display remains always black, until reset.
Support forums did not help much - people talk about this problem for a couple of years already, some advice updating BIOS, but this did not work in my case. Only the stock image from Lenovo Recovery CDs seemed not to have this problem (but did have Superfish and stuff ;-) )
Solution appeared to be quite easy - I just needed to install the latest Intel HD Graphics Driver :) That’s it. Here’s the location of this driver: https://downloadcenter.intel.com/download/24785/Intel-Iris-and-HD-Graphics-Driver-for-Windows-7-8-8-1-64-bit
It just seems that Lenovo System Update software does not update this driver automatically.