Unable to Save from CMOS Setup Utility

I am unable to continue after a SAVE & EXIT from the Award - Phoenix CMOS Setup Utility.

When doing a SAVE & EXIT or F10
dialog asks Y/N ?
After doing a Y & ENTER the screen just hangs.

ECS 865G-M mobo v2.3 (478)
Celeron D 345 (3.06)
2GB DDR
new BIOS chip with v1.1c
good battery
all jumpers correct
Tried flashing to different BIOS version
Tried several new keyboards, PS/2 & USB.

strange, how about leaving only the basic components in e.g. RAM, video and disconnecting the HDD etc to see if if it hangs or not…

The board is on a test bench
minimal hardware
good battery
good flash
both jumpers correct
clock 133x23 (~3.06)

The boot stops with this warning message:
Warning! CPU has been changed
Please re-enter CPU settings…

I use delete to enter CMOS Setup Utility
select optimized defaults
accept the Yes and enter
select SAVE & EXIT or F10
accept the Yes and enter

then system hangs

Ctrl-Alt-Del

reboot does the same thing