garmin sat nav?

i recently bought a new charging lead for my nuvi 200 it isn't an original garmin product and when i plug it in, the sat nav powers up but it just stays on the same screen which has the word garmin with a little picture of a computer and a sat nav plugged into it. I have tried plugging my device into the pc, but it just says that there are no updates ready for my device. what is wrong with it help!!!