I have a MacBook Black 2.2Ghz Merom. Installed 200GB 7200rpm drive and 4GB aftermarket RAM. I keep having seemingly random lockups. I can still move the mouse around the screen but clicking on anything results in nothing - whether it is an application window or even the Apple at the top left of the screen. This happens anywhere from 10 minutes to hours after I do a clean boot. I do notice that the FAN seems to stay at ~6000rpm almost constantly even when all I am doing is browsing or listening to music. Is this normal? The thing sounds louder than just about any other laptop I have had. Temps seem to hover at around 150F for the CPU. Any ideas?