My TomTom Start 25 S/N BQ will not connect to my laptop. I have tried using a different USB cable and tested my TomTom cable with another device. I have followed all the advice on your website about managing devices and Network settings, but my TomTom appears nowhere. I have tried connecting the TomTom to a different PC and that doesn't recognise it either. I have reset the TomTom, restarted dozens of times, checked for Windows updates but nothing works. It has always connected immediately before and updated maps etc without problems. What is wrong?