Their shutdown issue was about a game. They found they couldn't shut down after the game. Once they logged out, I think they said it would shut down.
The startup issue is likely hardware. I see very little about the PC so how about a SPECCY plus the make/model of the PSU.
How is at https://www.piriform.com/docs/speccy/using-speccy/publishing-a-speccy-profile-to-the-web
I seem to be getting the same problem that most people are having, the display being black but the computer gets through the post setup. And the solution every time was to reseat either the RAM, GPU or sometimes both (well more often than not).
My question is, is there some interaction between the RAM and GPU that may/will cause problems if the PC is not shutdown properly, or in some cases even when shutting down normally.