Your Garmin GPS device can be a powerful tool when you’re driving through uncharted territory, but the device won’t be much help if you can’t get it to power on. In most cases a hard reset can resolve whatever software problem the device is experiencing and clearing out software bugs will allow your device to boot cleanly.
Perform a Hard Reset (Nuvi 30, 40, or 50 Series)
Disconnect your Garmin GPS device from its power source.
Press and hold the lower right-hand corner of the touchscreen. Turn on the GPS device while keeping your finger on the display.
Wait for the “Erase all data?” prompt. Select “Yes.”
Follow the onscreen prompts when your device reboots. This should clear any software issues preventing a boot.