After replacing my micro processors awhile back (catastophic failure - gray boot screen indicating an error), everything was working fine. As of lately, I have noticed that when doing intensive work (Final Cut, etc.) that the computer will freeze and require a restart. Running the CD repair disc indeed has revealed a problem regarding "an inability to access memory address locations..." (I immediately swapped my memory in, out, and all around - no change; 4 sticks of Crucial 512s, which have not given me problems in the past in ANY of my machines). I have therefore come to the conclusion that I now must replace the main logic board. Question: where can I find the part number to ensure that I get the right one to ensure dual-boot capability (which this particular model was designed to do)? Many thank in advance!