Reset your Chromebook back to factory settings by doing the following:
1. Sign out of your Chromebook.
2. Press and hold [Ctrl] + [Alt] + [Shift] + [r].
3. Select [Restart].
4. In the box that appears, select [Powerwash] > [Continue].
5. Follow the steps that appear and sign in with your Google Account.
6. Once you've reset your Chromebook, follow the onscreen instructions to set up your Chromebook.