My Mini just spontaneously shut itself off in the middle of a web-browsing session. It didn't go to sleep from non-use, because I was actively using it. I hit the power button and it rebooted fine, except Camino was now unable to connect to any websites. So i shut down/rebooted again and now everything seems fine. No surges or other electrical problems, as far as I know. No other components lost power. It's never done this before. How do I troubleshoot it? Or do you know what it might be? Cable modem glitch of some kind?