I tried to update my tomtom, but it is frozen and just says there is a corrupted map, but I can't delete it, or replace it, and as I have lifetime maps I am less than happy. My tomtom is model 4EN42. And I have the IT skills at the same level as my cat. I don't think there is enough memory, but having found a slot for memory card, can't find one for sale. Is this Tomtom telling me to stop driving?