Restarting your chromebook can resolve a lot of issues you may be having if it has not been turned on for a while or shutdown properly and needs an update.
Checking for an Update
Click the bottom right area where the time is
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Click the settings cog wheel icon
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Click About Chrome OS on the bottom left side:
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It will show you the version you are running, click Check for Updates if available and let it download the update if available:
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If no updates are available it will will state that it is up to date:
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Restarting Your Chromebook
Click the bottom right area where the time is:
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Click the power icon in the list:
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Wait until the device has completely powered off then press the power button to turn it back on.