I offer this advice for anybody who's interested. I'm not recommending this procedure, or advising it, but if you suffer from the same symptoms as I did then it's worth investigating. My MacBook's fans had a habit of spinning up at the drop of a hat. Even just playing a YouTube video, or visiting a Flash-heavy webpage, could do it. Using Photo Booth caused the fan to spin up too. Back when the MB and MBP were launched, I read that the Apple service manual advises engineers to use too much thermal compound on the CPU-heatsink. This had an insulating effect, making the chip warmer than it needed to be. People reported that if they disassembled their notebooks, cleaned the CPU and heatsink, and reapplied less silicon, then they were able to run their computers a few degrees cooler. Well, I gave it a go, and they're right. It works. The fans on my MacBook are quite a bit less inclined to spin up and I can even run VMware Fusion without them getting hot and bothered. It hasn't stopped them spinning up completely, of course, but it's an improvement. The MacBook is a supremely serviceable machine, and once the keyboard panel has been removed, it's a piece of cake to get at everything on the logic board. The FixIt site has a good guide to disassembly: http://www.ifixit.com/Guide/Mac/MacBook/86/ The heatsink/heatpipe mechanism comes away easily and I was able to clean and apply small dabs of silicon. I used Akasa silver-based compound. You'll need to clean and regrease the CPU and GPU chips, which share the same heatpipe arrangement (in my 1.83 machine, at least). I've had experience of building PCs from scratch, and I wouldn't advise anybody do this unless they know what they're doing. And, of course, you will invalidate your warranty. But it's well worth it if you have a noisy MacBook, especially considering the 12 month warranties on the first run of MacBooks are now coming to an end.