Here's how you can do a fast restart of your Chromebook by pressing a couple of keys.
1. Press and hold the Refresh and Power buttons.
2. Chrome OS will shutdown and reboot.
If your Chromebook has been running slow a reboot might help speed it up again.
Chrome OS keeps improving and with new features come new ways to get things done. Here’s a list of 10 new tips that could be handy for those with a new Chromebook or Chromebox.More at Gigaom
Additional resources for Chrome OS