Howdy. I have a late 2006 MBP (2.33 ghz intel core 2 duo) that I'm trying to nurse along until the next MBP update. It might not happen, but one can always dream. Recently I've noticed a strange moment when starting up, which makes me wonder how tenable my dream may be. This pops up o the screen, just before my desktop appears. any ideas as to what may be causing the checker board effect? if it helps, my motherboard died over the summer of 2011, and i had it replaced.