I wish you luck, I had the same problem with tomtom700 (520£) 29 months old. Contacted support 6 times never got a suitable answer to my questions. Have sent it back. Answer: replacement will cost 180£ no breakdown of problem nothing. For 140£ I can get a satnav from Argos with 3 years guarantee and no one will tell me Tomtom is better because obviously it's not.
Daniel Gozin
Daniel Gozin, May 2008