I am surprised that I have the same problems with my recent TOMTOM (Special camping car model.
I was very happy, days, until he no longer recognized as valid GPS signal.
Since then, from time to time, connected computer on the site TOMTOM home, he leaves and logs;
It alternates between classic wallpaper, a black background, with ToToM LIVE listed on the left side,
then back on classical wallpaper.
Sometimes the equipment off and on again (reset?) It off again.
Conclusion ..
Bad buy (besides the company itself-even is in trouble.)
disappointment