Hi all,

Really hoping someone can help me with this. Day 2 of troubleshooting I am at a loss.

/Specs

Motherboard: MSI B550 TOMAHAWK AM4 (brand new) CPU: Ryzen 7 5800X (brand new) GPU: Nvidia GeForce GTX 1080ti (used, working in old system) RAM: 2x Corsair Vengeance DDR4 3200mhz (brand new) PSU: Corsair CX850w Bronze

/Problem

System will not post at all, I get a flash of light on gpu, ATX indicator light, and a 1/32th turn on PAU fan and system fan (nothing on cpu fan)

Interestingly, the same indications (lights and fans) also happen about 3 seconds after the PSU has been turned off.

/Steps tried

Replacing the motherboard

Using only 1 stick of ram, in each slot

Trying a different ram stick (DDR4 hyperX)

Trying a different PSU

Downloading latest bios update to fat32 formatted usb (under 16GB) and renaming to “MSI.ROM” and initiating a bios flash with flash bios button. Flashing appeared to be successful, for 5 minutes I had gpu lights, motherboard RBG and bios flash led indicator flashing, then the lights stopped indicating flashing was complete. After that, the system still will not start, and I can no longer get that far (I tried to initiate flashing again, nothing happens)

Reseating the CPU

Display port on GPU and Rear IO slots

Any help much appreciated!

Imgur link with video: https://i.imgur.com/lwYvP1g.mp4