This issue sounds software related so I have included some instructions below on how to update your system software and master reset the device. This should hopefully resolve the issue you are having. Please let me know the outcome of this.
If you have the latest software please select to reinstall it.I hope this helps resolve your problem.
Software update........................
The preferred way to update the Software in a Garmin device is by using WebUpdater. WebUpdater is a free application that can be downloaded and installed on your computer. It will guide you through the process of updating the software for your Garmin device. WebUpdater can be run at any time to check and install applicable Software updates in a Garmin device.
Starting at the WebUpdater page: (http://www.garmin.com/products/webupdater/howtoinstall.jsp)
1. Plug your unit into the computer via the USB cable
2. Click on Download under step 1
3. Select the appropriate version of the WebUpdater based on your computer's operating system
4. Click I agree to the above terms and want to proceed to the download page
5. Click Download
6. Select Run when the pop up box appears
7. Select Run if a message appears asking "Do you want to run this software?"
8. Click Next when the WebUpdater installation page appears
9. Check the box to accept the licensing terms and select Next
10. Select Done to complete the WebUpdater download
Once WebUpdater is installed on your computer, select the application, if it does not automatically open, to run the program and follow the prompts.
1. Select Next on the WebUpdater Wizard
2. Select Find Device and Next
3. Select Next to update the unit software on your device and follow the prompts
Once you have run the software updates and updated your device, you will be prompted to search for additional updates. To load any additional updates, check the box next to the specific updates you wish to download. Select anything that relates to firmware, GPS software, traffic, vehicles or voice language relating to the versions you use. Once selected, click next and check the agreement box. At this point the updates will run directly to your Garmin device. Once the update is complete you will see a box showing the downloads and if they were a success. Click finish and unplug your Garmin from the computer to allow the updates to load. Once the update(s) are loaded, your device will return to the normal agreement screen and it will be ready to operate.
Master reset...................................
Note: A master reset will erase all waypoints or favorites and will restore your unit to the default factory settings.
1. Start with the device OFF and unplugged from the power source.
2. Press and hold the bottom right corner of the touchscreen.
3. Power the device ON while continuing to press and hold your finger on corner of the touchscreen.
4. After the device powers ON, you will see the message: Do you really want to erase all user data?
5. When this message displays, remove your finger from the touchscreen and touch Yes.
6. The device will now go through the Reset.
7. Follow the onscreen instructions to set up your nüvi.
After the nüvi is set up, if indoors, please go outside to allow the device to acquire the satellite information. Ensure that the device has a clear line-of-sight with the sky. Allow up to 45 minutes for the first GPS fix.