This an odd one. I just picked up the sim but can't seem to start a flight after the first day. When I try to start a flight, it loads up, and I get the cockpit, then the ground texture, but the moment it tries to load any of the buildings and trees and such, the computer reboots.
It's specific to that particular moment, and it doesn't matter what plane or airport I use.
I don't think it's anything heat related as I don't have any other issues with other games on this system, and even when running crypto mining on it to test, my system, gpu and cpu all stay cool enough. This is the only software on my system that can cause this reboot to happen.