no the BIOS nor other device will shut down when they get too hot what the system will do is lock it self forcing you to reboot. But if you are not at home when that happends it would be worse because they may get even more hotter than before and start a fire .HOWEVER I HOPE THAT NEVER HAPPEND TO ANY OF US OR ANY one else
you may find some software over the internet that monitors your temps on the CPUs and if they get too hot it will shut down dont remember the name of the software
And i sleep really close to the PC so if anything happends i would be the first to know and my PC has 8 Fans on the case blowing in and out and the CPUses have fans of 7000RPM and the Power Supply has 2 fans
the only thing that concerns me is the Power Supply when i am away from Home i dont know it gives me a weird feeling.
However i only leave on when i am at home
a bit long isnt it?