Try a hard reset only after other ways to fix the problem have failed. It will restart your Chromebook hardware (like your keyboard and touchpad), and might delete some files in your Downloads folder.
Reset Screen Resolution: Shift + Ctrl + 0
Take a Screenshot: Ctrl + Show Windows
Turn Caps Lock On or off: Search + Alt
Remove your user account if you're experience any browsing/cache issues, then sign back in.
Forgot Password? - Click on 'Reset Password'
Forgot Username? - Click on 'Claim My Account'