Completely safe as long as you keep an eye on your Motherboard Temps.12 Dec 2016
How long can a PC run without a fan?
you can run the CPU for about 20 seconds, before it gets to around 60-70 degrees. this is plenty of time to see if the computer POSTs correctly.20 Feb 2011
What happens if your PC has no fans?
CPUs with dead fans will overheat. The CPU can get so hot it will ignite, destroying itself beyond repair. A fried CPU can also take down the motherboard and other connected components with it when it goes. The CPU will break if the computer is continually used with a dead CPU cooler fan.
Can you use a pc with no fans?
Yes technically the build has fans, the computer can be used with fans in an off or disabled mode, essentially meaning zero fans being used. But rather than "fanless", I believe you mean "passively cooled" computer, as that's more or less what it would be.
What happens if a computer has no fan?
Without a fan running the computer will overheat and shut off to keep from damaging the motherboard. It will not power back on until it cools off. Replace the fan or if it is a laptop buy a cooling pad that has fans on it and you plug it into a USB port and sit the laptop on it to keep cool.