While you check that out, have you reset the computer to release excessive static? Use Step 3 for steps.
Step 1: Remove external devices
If your Chromebook does not start, remove any and all USB devices, and remove memory cards from the card reader slot. Disconnect all non-essential devices (external hard drives and similar).
After you have removed all external devices, turn on the Chromebook. What happens?
If the Chromebook starts, reconnect devices one at a time while restarting the computer to figure out which device is causing the problem. You are done.
If the Chromebook still does not start or exhibits the same problem, do not reconnect anything, and continue troubleshooting.
Step 2: Find a fix that matches your Chromebook's symptom
If your Chromebook does not start, read from the following list of symptoms. If you find a symptom that matches your computer's condition, follow those instructions. You might be directed to another support document containing detailed troubleshooting procedures. If you cannot find a symptom that matches your computer's condition, proceed to Step 3: Perform a hard reboot.