Answer to "One Ram slot gone Bad.."McGyver repair Situation: My problem was getting random freezes, artifacts and failed start-ups with the three bleeps. I thought i had traced the problem to one of the RAM sticks (16gb upgradekit), got a new stick from RMA and it had problems immediately (yes i crossed checked, including an extended system diagnose). On to the repair: Macbook was pretty clean, no dust in the slots. Used a compresses air, no luck. Thought of using the ol' contact cleaner'n'toothbrush method.... but didn't have any contact cleaner at hand. I just raked the slot pins with the same philips screwdriver i used to open the backplate and have had no trouble since (including two extended apple system diagnoses and heavy app usage). When raking you will find the pins flex a little, as if running your finger down tight blinds, maybe the contact just making flaky contact if your system wasn't completely dead beforehand i.e. random freezing, crashes and artifacts.