To be used if no other help documents have solved your problem
Reset Chromebook to Factory State
This usually fixes any possible issues with the device. It should work to fix the issue you are experiencing.
Press and hold esc + refresh, then press the power button. (The refresh key has an icon that looks like a circular arrow pointing in a clockwise direction. It's in the fourth key from the left in the top row of the keyboard.) The picture below has the keys circled.
The Esc + Refresh + Power keys
There will be a big yellow ! in the middle of the screen. Depending on the current version of your ChromeOS, this will be one of the two images below.
Older Chrome
Newer Chrome
Even though the screen says "Chrome OS is missing or damaged. Please insert USB stick", You do not need to insert a USB stick., instead press Ctrl and the letter D.
Now press enter.
You will be presented with a screen that says "OS verification is OFF, press SPACE to re-enable" At this point press the spacebar.
Verification OFF
Verification ON
On the next screen, press enter to initiate the process of reinstalling the operating system. This will take a couple minutes, but then you should be able to connect to your wifi
Completed
Click on Let’s go >
Choose your wifi account
Click on Next >
Click on Accept and continue
Click on Done.