when did you but thay and how old is it?the 510 has about 6 different series. if you look on the back it wil say t510 a or t 510 e or something. if its one of the first ones it needs new maps and needs to be updated. that should fix most of your problems. however it isnt 100%.you also need to make sure its not on car mode.i hade the very first one a 510a and it froze up on me.then they sent me a 510e to replace it and i havent had a problem yet with the new one.it is way better and faster than the old one also