Power buttons on the Garmin nuvi usually fail because of the way they are constructed. The button itself is merely soldered to the motherboard, and there is nothing holding you back from pushing too hard, and snapping the connection. In most cases, you can resolder and put a piece of plastic that will reside between the SD card slot and the power button. You will need about 1mm thick plastic. We got ours from the top of a yogurt cup. Wedge the stopper in and put the nuvi back together.