HP/Compaq :: Nx9105 Replacement Mobo

I just replaced the motherboard in the girlfriend's HP/Compaq NX9105 (died in a wine spill...). The new mobo boots, but the first message was "unsupported wireless network device detected" and the system went no further. So I removed the card figuring a BIOS upgrade would sort that, but then I am faced with the message "this motherboard does not support 82W CPU", and again the system goes no further. I have checked the parts list and there only seems to be one mobo for this model, although there is one figure different on the part number:
Old mobo SPS-370495-001
New mobo: SPS-370496-001

The only other difference I could find was the new mobo only has one CPU fan header, easily sorted.
Other details;
CPU Athlon 64 1800 Skt 754
1.5GB DDR1 (though just using 256 stick for testing)
Bios Ver F11, newest available F34.

AFAIK the 1800 was the slowest CPU offered on this model except for some that had an Athlon XP-M fitted.

This may just be a BIOS upgrade issue, and I can certainly enter setup, but at the moment I cannot get it past the error messages, so any pertinent advice gratefully received.