it's PSU faulty, i tried to boot only with cpu, stock cooler, ram and mobo but both the psu fan and the cooler fan only spin a second, i tested with case fans plugged on the motherboard and the same thing, i suspected either the psu or the mobo have problems, then i took apart the psu and tried the paperclip test but the same! the fan spins less than a sec only.
The psu is a NZXT hale82 v2 550W modular
The psu is a NZXT hale82 v2 550W modular