How to Force Reboot a Frozen Mac
Though Macs are known for being stable and experiencing considerably fewer crashes and system freezes than some of the competition, the reality is that sometimes stuff still happens. Typically it’s just an app that crashes or freezes up, remedied with a force quit and relaunch, but on rare occasions the Mac will freeze entirely, with Mac OS X becoming completely unresponsive to anything, from keyboard input to even the inability to move a cursor. This is often accompanied by fans blazing quite loudly, demonstrating a truly frozen Mac, and when this happens the computer is basically stuck in that state until you intervene.