Hello, Sorry you're having problems. Please connect your Nuvi 350 to your PC using the included USB to micro-USB cable (if you do not have that cable then you can purchase one at the link below):
Then click on the following link, and follow the instructions to setup a Garmin Express account and follow the instructions there to update your GPS:
If you need further assistance let me know. Before you go, PLEASE DO click at least a 3 STAR RATING, at the top of your screen (scroll up the page to get to the STARS). That is how I am credited for my efforts by the site. You can follow up any time as needed at no additional cost.
Please don't post duplicate questions. Follow the instructions on this page and if you get stuck simply reply back. Let me know if you need more help. Also, could you please click a POSITIVE RATING (3-5 stars at the top of the page) and click SUBMIT so that I am credited for working with you today?