[SOLVED] CPU won’t turn on and when it does it sometimes cuts off

[mattman3500]

So, I’ve been having this issue for a while, but I can’t tell if it’s a cpu issue or a psu issue. Sometimes, when I try to start my computer, the lights on the CPU fan won’t turn on, and the cpu itself is unresponsive. I have tried several solutions, including reseating and replacing the CMOS battery, reseating the gpu, and reseating the ram. I also tried turning it on with minimal setup: 1 ram stick, no gpu. It turns on then, but it’s still finicky. At this point, it feels more like a psu issue, but Im still not sure. Looking for any thoughts or recommendations on what to do. I don’t have access to any additional parts to test with.
Specs:
CPU: AMD Ryzen 7 2700x 3.7 GHz 8 core processor
Motherboard: MSI B450 Tomahawk ATX AM4 Motherboard
Memory: G.Skill Trident Z RGB 16 GB (2x8GB) DDR4-3200 Memory
Hard drive: Western Digital Caviar Blue 1TB 3.5” 7200RPM Internal Hard Drive
SSD: Western Digital Blue 1TB M.2-2280 Solid State Drive
GPU: MSI GeForce RTX 2080Ti 8GB
PSU: Corsair RMX (2018) 650 W 80+ Gold Certified Fully Modular ATX Power Supply

 

[Shektron]

Have you tried the usual solutions like a BIOS update, driver update? When the lights on the CPU cooler don't turn on, does the rest of the system turn on? Do the GPU fans and case fans spin up?

 

[mattman3500]

Have you tried the usual solutions like a BIOS update, driver update? When the lights on the CPU cooler don't turn on, does the rest of the system turn on? Do the GPU fans and case fans spin up?

I haven’t tried the BIOS update, and I don’t know how to. Everything else turns on. Lights on the motherboard, ram lights, other fans, gpu fans. The cpu and accompanying lights and fan don’t turn on

 

[Shektron]

I haven’t tried the BIOS update, and I don’t know how to. Everything else turns on. Lights on the motherboard, ram lights, other fans, gpu fans. The cpu and accompanying lights and fan don’t turn on

For the BIOS update, go to your motherboard's official website, from there you will find the latest BIOS file, probably in Support or Downloads section. Put that file on a USB, preferably a blank USB, and go into the BIOS with that USB plugged in. You'll find the update BIOS option in the BIOS itself, from there you just select the BIOS file and let it update. Remember, the power should not be disrupted when the BIOS is updating, or the process should not be interrupted in any other way, or you could brick your motherboard. Once the update is complete, the PC should automatically restart and boot into Windows normally, and you can remove the USB once in Windows.

P.S : The update BIOS option is probably called M-FLASH or something similar. You can probably read a description of the option before using it in the BIOS itself, my board is somewhat similar to yours (MSI B350 Gaming Plus) and the option is M-Flash in my BIOS.