Turn your computer off and then disconnect all media devices such as USB drives. Next disconnect the AC power adapter and then remove the battery. Perform a hard reboot by holding down the power button for 7 seconds. Finally, reconnect the AC power adapter and turn the computer on without the battery connected. IF the Chromebook starts up normally you have finished the hard reboot.

You can’t remove the battery on most Chromebooks; the unit is sealed so the battery is inaccessible, unless you’re suggesting dismantling the Chromebook and invalidating any warranty/insurance a user may have.