In some nuvi models there is a reset button.But in some nuvi models there is no reset button.you have mentioned only garmin nuvi but not mentioned the model of the garmin nuvi.But still i will mention the reset button location of some garmin nuvi models.Hope that helps you.
The reset button/procedure for garmin nuvi models
In order to reset Garmin device or enter into maintenance mode, perform one of the following procedures:
Power off Garmin unit. Press on continuously the upper top left corner of screen and then power on the unit by pressing once on the Power button. You should be prompted to clear all user data, or asked if do you really want to start up in maintenance mode. Press “Yes” to reset (warning: all data will be erased and lost, so backup before proceeding) or enter maintenance mode.
above works on Garmin Nuvi 660, 680 series.
Turn off Garmin device. Press down on bottom right corner of the touchscreen, and then power on the GPS unit. You should be prompted whether do you really want to erase all user data, or asked if do you really want to start up in maintenance mode. Press “Yes” to reset (warning: all data will be erased and lost, so backup before proceeding) or enter maintenance mode.
above works on Garmin nuvi 200, 250, 360 750, 760 series unit. Garmin Nuvi 360 on how to perform the hidden reset function.
Reset button on the bottom of the nuvi backside.
Click on the link below to get the exact location of the reset button.http://www8.garmin.com/manuals/1512_SetupandGo!.pdf
also check out this link too
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