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I would advise turning it Off for several hours. Then after that interval, try connecting it to a computer that has Garmin Express installed on it, and running. That may update or restore the Garmin software on the device and restore operation, hopefully.
Simply download, install, and use Garmin Express.
and (if you have a Windows PC) click on the big blue Download button at center bottom of the page. (If you have an Apple, click on the nearby Download for Mac link.) And download Garmin Express' installer to your computer, save it, then double-click upon it to install Garmin Express.
Then start the program, Garmin Express. Then connect your Garmin device. Then use Garmin Express to update your device.