I removed my N. America maps to a folder in order to install Britain on my XL IQ 340- returning home, removed Britain to a folder but on attempting to re-install N. America I get constant 'no maps found' If I look in the folder on the computer it shows the maps are there. When turning on the device it shows briefly a colour photo of a bridge then turns to a screen showing only the picture of the tom tom &* Tom Tom XL IQ Routes in upper right corner. I can get nothing more. Please help!!