Software cannot shut down a computer. It's impossible.
Sorry but this is just not true. Software shuts down a PC all the time, how do you think Windows can shut down a computer? Over the years I have seen Windows cause system shutdowns through file corruption as well. It is not common but it can and does sometimes happen.
Windows is a special case as it's the OS. A video game cannot and will not ever be responsible for your PC shutting down. That is always a hardware issue (overheating, insufficient power, improperly seated components, dying hardware, etc.).
These posts are common on the forums of every game. They are always hardware-related.