There’s a strong belief amoung non-technical people that home computers should not ever be left on unattended – since they are electrical devices and can go up in flames and set the room on fire.
Now it’s obvious that any component inside the computer system unit can break at any moment and maybe even produce a fair share of toxic smoke. But do computers actually go up in flames that can cause a fire around them?
Solution:
I think we should distinguish between ‘conflagrations’ which emit a little smoke, and overheating which might cause fires by contact with something flammable.
Reputable computer hardware manufacturers use components which do not accelerate fires and are flame-retardant so far as possible.
The Underwriters Laboratories rating system requires these things, but Gnoupi is right about power supplies: don’t buy very cheap “noname” power supplies: they may have been designed with no regard for safety considerations.
But, by and large, computer system unit don’t go up in flames … although there may be a few exceptional ‘cases’.