The computer won’t start fan blows high speed means the problem is heat. So, you should find out the cause and then take the proper step to solve the problem. Although, most of the cases motherboard failure is the cause of blowing the fan with high speed and no display. But, we have shared several reasons for this occurrence.
Computer won’t start fan blows high speed – troubleshooting
Unplug the power supply wire: A little thing can help to work your PC again, unplug the cable that comes from the power supply to the CPU on the computer motherboard.
Heatsink and CPU Thermal Compound: If the fan running at high speed, there is a great possibility of heat problems. Because the fan producing a lot of air to reduce the heat.
So, check the heatsink. Also, try to replace the thermal compound of the CPU if it fixes the problem.
Clean up all components: Clean all the access able spot of the computer like the heatsink, fan, inside of the case, etc. Dust removal can solve the issue.
The motherboard: The motherboard tells the fan to become slow when it measures the temperature of the processor and get everything Okay and Cool. But, your motherboard is unable to complete Power On Self Tests (POST). That’s why the fan is not getting command from the motherboard to be slow down. Replacement of the motherboard can be the solution.
The Processor Fan: Maybe your processor fan defective, that’s why causing the system to overheat and the fan blows at high speed. Replacing the fan can resolve the problem.
Another tip for you when the computer won’t start fan blows high speed, try to unplug everything you can such as memory stick, CD/DVD, CPU fan, battery, USB devices, etc. and plug them again.