Question Troubleshooting - PC boots sometimes, often doesn't boot and fans spin at full speed - can't find issue or fix


Dec 13, 2014
Hi, posting for a friend here. I've been messaging him trying to figure out the issue. the issue is that the PC only boots up when it is in the mood to. most boot attempts result in the fans spinning at max speed as they tend to at the start, but staying at max speed and not going into POST and booting up properly. He usually just spam boots it many times until eventually it boots up properly, and when it does boot up properly it works without issues.

he has a gigabyte motherboard ga-p61-usb3-b3, a 470 watt psu, HD 5670, i3 2xxx dual core cpu
mobo only has 1 pci express slot that supports his gpu, no integrated gpu output
link to pic of mobo:

specs of PSU:
Dual +12V rails​
2rails +12V design, capable of supplying high power output.​

So far he's tried:

-booting without GPU (fans do not spin at full speed, so we thought the GPU was the problem, however, he doesn't hear the usual beeps he hears when pc boots up normally and he tried hearing for sound for Windows startup, couldn't hear any. he does not have another display port so a GPU is required to see anything since there are no integrated graphics)
-booting with another weaker GPU with lower power draw (no signal, tried different cables and different outputs. fans do not spin at full speed, which could be indication that it boots but the no signal part, and no startup beeps/sounds is strange)
-booting with peripherals removed (mouse, keyboard, usbs)
-booting with different ram sticks, also from other computers, with single sticks tested in each slot
-cleared cmos to reset bios
-replaced cmos/motherboard battery
-ensured every cable was plugged correctly and firmly, re-seated GPU
-tried to open up main BIOS chip to inspect pins/connection, but could not. gigabyte motherboards apparently solder their bios chips, and have 2 bios chips, a main one and a backup one with default settings. we tried to force it to boot with backup bios chip with 3 different methods., such as holding down the power/reset button at same time for 10 seconds. after removing the gpu to stop the fans spinning, we did this and it restarted, which may indicate that the backup bios chip was used, but it still doesnt boot properly after GPU is put back in.

the only way we managed to stop the fans from spinning at max speed was by removing the gpu/replacing the gpu. but there is still no sign of it booting/cant check with 2nd gpu because it doesnt output anything. so this is confusing. could very well be a GPU problem, but the other GPU definitely works as it was taken out of a working system, so why no display? and when the pc does decide to boot properly, the GPU works fine for gaming.

what we found weird was:
-pc was working without issues with the previous owner for many years, until suddenly it started having booting issues with the fan spinning at full speed constantly, not going to POST, which my friend is now experiencing. it did sometimes boot properly after many attempts, but when it did boot it ran without issues or crashes
-when it boots, works fine without crashes or issues so it doesnt seem to be a RAM or CPU issue, or even GPU issue although we're not ruling out the GPU just yet as fans do not spin at full speed without the gpu/with another gpu that gives no output
-he checked all cables, ram, to ensure it wasn't just a matter of loose components

any pointers?
Last edited:
Apr 14, 2019
First off I would try giving everything a good cleaning. It may be something as simple as dust causing arcing and the motherboard protecting itself and not booting up. Clean it see if it helps.
I cleaned the pc for good, it launched some attempts later after the cleaning but the issue kept occuring after