Question Z790 PC shut down abruptly when using and stucks at MB logo when booting

[Fording's Jump Hack]

Hi guys.
Last week I just built a new pc with Gigabyte z790 aero g MB, 13900kf CPU and DDR5.

It ran well in the past 5 days, but today it stopped working.

When using it, it shut down abruptly. Then it stucks at the MB logo every time booting up.

I guess the CPU and DDR5 are fine because I can even run memtest86 using a USB.

But I cannot locate the problem.

I took out the MB battery, but didn't fix it.

I don't know how to downgrade the bios to factory version. I don't have a laptop so cannot download the old bios.

Any hints will be appreciated!

 

[Dark Lord of Tech]

FULL SPECS?