I purchased the USA map for my TomTom 25 Start device, however, there's not enough memory to install the entire map.I have installed a smaller map of the south west but purchased an SD card with enough memory to hold the entire map. The SD card is successfully installed on the device but MyDrive connect won't install the map as there appears to be no way to switch the SD card storage. I've tried connecting the SD card to my desktop through the card reader, but nothing happens. Does anyone know how to get the SD card active on the device and MyDrive so that the additional memory can be used. Any suggestions would be appreciated as there would appear to be no instructions available.