Wierd processor problem

[daweseyco1]

i have two systems(lets call them A and B) both lga775 processors. recently one packed up and after a lengthy diagnostic process i finally deduced that it was the motherboard or the processor. so i swapped them. wierd thing is if i swap them they work. so i put system A processor into system b and it works and vice versa, i put system B processor into system A and it works also. is it the processor or is it system B's motherboard?

 

[enzo matrix]

Wierd.
But what do you mean by "Packed up"?

 

[jsc]

Specs on both systems?