I have a 2.0 GHz Core 2 Duo MacBook purchased just about a year ago (so if this is a hardware issue, I need to get it in to the Genius Bar STAT, I should have about a week or two left to my warranty). I upgraded to Leopard last week (thank god, actually, because that got me to back everything up if this is dead) and since then the fan on my laptop has been going crazy. My battery usually lasts a good three hours, but now it barely lasts 1.5, because the fan is going non-stop. This is plugged in or not plugged in. Just now, the fan actually wasn't going, and though it felt a bit hot, I wasn't concerned. My computer was functioning perfectly normal. Nothing was hanging up or anything. And then, with zero warning, the screen went black. I turned the computer back on and opened two applications (iChat and Safari, though Microsoft Auto Update did update Word). It was fine for about five minutes, and then it went black again. Any ideas about what's wrong with it? On a possibly related note, when updating to Leopard, I noticed that my 667 MHz memory was only running at 533, which, according to my research, is a defect common with Patriot memory purchased through Newegg. I am getting this taken care of, but I have no way to know if it's at all related. Just figured I should mention it in case that could have something to do with it. Though I ran Tiger with that memory since June, so I doubt it.