The error indicates ***embedded controller has timed out waiting for the BIOS to return from system board initialization*** (end of POST).
That means......either the BIOS is hosed or something on the MB isn't talking to the BIOS during initialization. I had that issue with a defective USB circuit on a laptop. The POST just hangs.
So, start with the easy stuff and try to replace the BIOS as suggested. If that doesn't work, it is likely a MB hardware problem.