On Mon, 2020-11-16 at 09:58 +0100, hw wrote:
[...] Put a minimal amount of RAM in and go through all of the modules to see if one or some of them are broken.
Replace all RAM or test it in another computer.
Replace the power supply.
Replace CPU or test it in another mainboard.
Replace mainboard.
If the board has a backup BIOS, use that to boot.