I unplugged everything from my PB (Nano, keyboard that has mouse and Treo 650 cradle attached, speakers, power plug and external monitor) and moved to a different room. When I opened the PB and clicked to open firefox and thunderbird I got a window pop up that said I needed to hold down the power button to shut down and when I restarted it said that OS X unexpectedly shut down and I could click OK or report and I clicked report and nothing happened. What would have caused this?