i7375 black screened and shut down. 

When attempting reboot, there was power but no Post, with 2 4 error code indicating RAM failure.

Opened up laptop and reseated/swapped/isolated Dimms to No effect (except when removing both Dimms resulted in 2 3 error code, ofc).

Bought new Dimms (Identical). Same 2 4 error code!! What??

Found similar laptop and tested new Dimms - no problem. 

Tested old Dimms in that similar laptop - tested FINE!! What??

Does anybody know what situations lead to a misdiagnosis of RAM failure?

Do you think the mobo is so messed up that it would give a misdiagnosis like this? 

Finally, other than buying a new mobo (~$200), are there any other steps I should use to troubleshoot? (Drained power, ckd Cmos, replaced battery all with NO effect)