My Macbook is my main machine these days, so it's on all day everyday. I've had it for just over a year now without any hiccups. However, earlier today, I was working away when all of a sudden it just turned off. No warning, no nothing. Just off. I pressed the power button to switch it back on, the DVD drive made it's little churning noise, but then it stopped and it didn't boot up. Was like this for 15-20mins, after which is decided to boot up. It's been running fine now for a couple of hours, but I'm a little concerned as to what caused the problem. I thought perhaps it overheated, but the Macbook sits on a desktop all day with plenty of air flow to and from it. Could it perhaps of been the battery or hard drive? Any suggestions are much appreciated. Cheers.