New Motherboard

[cliffyk]

You probably have done this, however--Recheck, double-check all connections--then check them again. Visually inspect them (sockets and connectors) with a magnifier looking for trapped debris; physically "run" each cable feeling for nicks, cuits, dimples, bumps, etc.

To the best of my knowledge the mobo should boot with no added firmware or "magicware", etc.

Elegoo's support is pretty good--keep in touch with them, they want you to a happy customer...