It appears as if software updates can get stuck installing on the Asus Chromebooks. When this happens the power light on the right side is lit but the screen is blank. Asus and Google have not been able to provide a fix at this time other than the workaround below.
Press the Power key and take a look on the right side of the device for a white light.
If there is no light, press the Power key again.
There should be a white light on the right side, but no image on the screen.
Hold the esc key and the circular Refresh key and then press the Power key.
The Chromebook will go blank and then show the recovery screen.
Press the Power key to turn the device off.
Press the Power key again to turn the device on.
The Chromebook should restart to the regular log in screen.