Fan running way to fast

[Brynyy]

Hey guys,
I recently built my new PC, when I turn it on it has normal fan speed, but after 5 minutes it starts going at full speed and it is very noisy. On SpeedFan it says my CPU Is 128C ( which is false ) and I think that is why my fans are running so fast because it thinks the CPU is really hot.
How would I fix this problem, thanks

 

[hiyabusared]

update your bios honestly. might need to update the bios to fix some stability issues and such.

 

[Brynyy]

Thanks, how do I update the bios ( sorry )

 

[hiyabusared]

Do you know by chance what motherboard you have?