I have been having this issue for a while now. I have reinstalled the pc, complete clean installation, changed disk, added memory... all to no avail. Wheneveer I want to restart, the laptop just shuts down. I am keeping up with all sorts of updates.
I have a ASUS S551LN, with 480GB SSD and 12GB RAM, Nvidia 840M 2GB, i5 4200
For a while, I managed to fix the problem by changing the Minimum/Maximum Processor Rate in the Power options to 100%. Worked for a bit and then it started again.
This is driving me insane as nobody can figure it out. I have been in chat with microsoft support more than once, they have remotely logged into my laptop and performed some test to see what the issue was and never found it.
Sometimes (not all the times), if I do a Selective Startup by disabling all services but Microsoft's, it will restart normally and then start again.