Question New PC build doesnt work

[Nalitej]

Hello guys,

I just finished my friends build and have issues.
My friend just upgraded some PC parts and PC doesnt boot.

Build is complete, but when i press start button no signal goes to monitor and whole I/O(rear and front) doesnt work. Every fan is working, every led aswell. And i can't turn off or restart PC once i turn it on with button, the only way i can turn off pc is by PSU.

Yes CPU is installed correctly, checked 2 times. Tried different PSU(connected just MOBO and CPU), same problem. Tried different slots of ram and just one ram, same problem.

Last thing i can try is to install new CPU to older MOBO to check if CPU is fine.

SPECS:
"-->" means what i have change from
MOBO: MSI B450 tommahawk --> Asus B550 tuf plus
CPU: Ryzen 5 1600x --> Ryzen 5 3600
Cooler: wraith max --> Scythe mugen 5
PSU: Seasonic 620W 80+ Bronze --> Corsair RM 750W 80+ Gold
RAM: 2x8 GB HyperX predator 3200 cl 16
Case: unknown --> MSI Vampiric 011c AMD edition
GPU: RX 580 Nitro+ 4GB
DRIVES: 1x Nvme 1TB, 1x sata ssd 128gb, 1x HDD 1TB

 

[Dj0gany]

Have you tried mixing ram slots?
Try putting sticks in different ram slots,and see if it works.
Also leave the pc with just 1 stick of ram,see if it works.

 

[Nalitej]

Have you tried mixing ram slots?
Try putting sticks in different ram slots,and see if it works.
Also leave the pc with just 1 stick of ram,see if it works.

Yes, but didnt try all possible options, because i can only turn off pc by PSU and i dont know if its healthy for the hardware. But i tried to boot with just one ram. Ram kit worked good in old setup, same as gpu worked good. The m.2 nvme and HDD is also from older setup.