I just got my new iBook today. It worked great all day until I turned it off to restart after I connected it to my college's network. When I tried to turn it back on, the screen stays black but the internal fan starts whirring very loudly. Nothing more happens, the fan just whirrs and whirrs and the screen stays black. Does anyone know what could have caused this and/or how to fix it? I did put in a 1.0 gig stick of ram which was recognized and functional for most of the day (I installed it practically right out of the box) but I don't think that is the problem because it worked for a long time. This shutdown was also not the first one since installing the ram. Thanks!