This sounds similar to a spate of threads that appeared recently on the Lenovo website. The problem was a bad graphics driver from Intel. If this bad driver is included in the Windows 10 update, that might explain the symptoms. See the following post for the solution:Just updated my HTPC (Intel GPU, latest drivers) to Win 10 1709 - now getting black screen on MP after resume from sleep...
Solved: Re: Lenovo Y720 sleep issues - Page 2 - Lenovo Community
-- from CyberSimian in the UK