[SOLVED] CPU fan immediately on as soon as i flick power supply on without pressing powr switch

[Jackattack99]

My computer i just built for my basement isnt posting and is doing weird stuff ive never seen before

CPU fan immediately turns on as soon as i flick power supply on, zero post verified cpu /ram/psu/gpu all fine working order(tested on other comp) , tried with onboard graphics also and nothing. Im thinking the mobo is shorted but is it possible its just a bios update ? mobo supports 3000g athlon cpu but this mobo i had kicking around for couple years in my closet was working fine before

system
asrock pro 4 b450
athlon 3000g am4 cpu
1060 gigabyte 6g gpu
750w evga supernova

i see no button or anything on mobo to update bios without post so im kinda scratching my head on how a cpu fan turns on as soon as mobo gets power without pressing the pwr switch

 

[CountMike]

My computer i just built for my basement isnt posting and is doing weird stuff ive never seen before

CPU fan immediately turns on as soon as i flick power supply on, zero post verified cpu /ram/psu/gpu all fine working order(tested on other comp) , tried with onboard graphics also and nothing. Im thinking the mobo is shorted but is it possible its just a bios update ? mobo supports 3000g athlon cpu but this mobo i had kicking around for couple years in my closet was working fine before

system
asrock pro 4 b450
athlon 3000g am4 cpu
1060 gigabyte 6g gpu
750w evga supernova

i see no button or anything on mobo to update bios without post so im kinda scratching my head on how a cpu fan turns on as soon as mobo gets power without pressing the pwr switch

https://www.asrock.com/MB/AMD/B450 Pro4/index.asp#CPU
Requires BIOS version P3.60 at least.