My Rider 4GD00 will not connect to PC

I have a Tom Tom Rider 4GD00 It was working perfectly until I recently updated it. Now it will not connect to the PC. The PC shows it connected as “Rider” but the device will not connect to TOM TOM Home. When the Rider is switched on I get the Tom Tom start up screen and then it switches to the yellow connect to PC screen. The blue icon in the left hand corner flashes briefly and then goes out and the screen stays as without offering the option to connect to PC. If I disconnect from the PC the screen eventually returns to the TOM TOM welcome screen but does not automatically turn off. I have to hold down the on/off button for 20 seconds.

Your assistance to get the Rider working properly again would be appreciated. The unit is fully charged and I have tried four different USB cables all of which have worked with the unit before.