I would suggest going down to the pub and getting drunk but..... that won't solve the problem.
I have to say that it is looking more likely that your motherboard is faulty and a final thing to try would be to see if we can get the Back-Up BIOS to kick in in case the main BIOS has become corrupted. If this doesn't work then I'm afraid I am out of ideas, other than RMA'ing the motherboard.
You can kick in the backup BIOS by shutting down the PSU from the wall, then hold down your case power button on and at the same time, turn on the power supply at the wall socket.
A few seconds later the board will start, immediately shut off the power supply at the wall socket.
Then you can turn on the power supply again and power up the board normally and DualBIOS should then kick in.
Hopefully you can understand this procedure OK and it should work. If not, don't panic there is one more thing we can try to get the back-up BIOS to kick in, if needed.