A8N-E Revert Bios back from 1013 to older Bios

Can anybody help with a problem please. I recenelty flashed the Bios on
my A8N-E from version 1008 to version 1013 in preparation for a new CPU.
The new CPU never happened so I decided to do a bit of overclocking
but the 1013 bios won't boot beyond the POST with any kind of overclock.

I would like to flash the Bios back to an older version but am unable to
do so. I tried the following:

1) Made a Dos boot disk with Bios and awdflash.exe but update tool
wouldn't let me flash to an older version
2) Tried using the Asus update tool from Windows but get an error "The
Bios cannot use in this motherboard. EEPROM different"

Also I have removed the CMOS battery, reset the CMOS with the jumpers
and tried booting from the motherboard support CD to see if the Bios
recovery tool would kick in but everything I have tried so far has not
worked.

Does anybody know how to flash the Bios back to an older version?

Thanks,
Andy