All of those methods have been tried, the only recourse is to blind flash the board. But in the thirty years of building I have never attempted a blind flash of the BIOS.You can borrow some other memory try to isolate the issue.
One or more memory stick(s) could be defective. Try boot with 1 memory stick only in recommended DIMM slot.
[test with each one of them alone]
Or could be bented pins on the socket or too much pressure from the heatsink and not to be the memory.
In anyways better open new own topic for troubleshooting the issue.