Ouch!
You can try and kick in the backup BIOS by shutting down the PC from the wall, then holding down your case's power button so that it is 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 kick in.
This will restore your BIOS to the version in the Back-up BIOS Chip. If you have updated BIOS to support a new CPU and the BIOS version in the back-up chip is older you may still have problems getting the system to BOOT as it may not recognise your processor. If this is the case you will need an older, compatible CPU to be able to continue.
Hopefully you can understand this procedure OK and it should work.