Mac OS X Lion adds a new feature that helps your Mac recover from crashes or freezes. I’m not sure how well it works since my Macs don’t crash all that often, but Apple built it into Mac OS X Lion so I might as well use it.
Open System Preferences, launch the Energy Saver control panel and look for Restart automatically if the computer freezes. If you want Mac OS X to restart your computer when it crashes or freezes activate it by clicking on it to add a check mark to the accompanying box.
Although I wasn’t able to test this feature in the field it is nice to have it if your Mac crashes. However, if it doesn’t work you’ll be forced to power off your Mac by pressing and holding the power button. Sometimes the old way might be the only way in this case..