TomTom Start 25 update fail

Hi, I have a TomTom Start 25 tomtom that a map update through Myconnect was attempted. The unit is not cracked as it has free updates. The update failed and the unit now says no maps installed. update has been attempted numerous times now and they all fail at various % of the update. A map update is one of the updates that is available. I have tried a reset but pressing the on button 3 times after the boot screen comes up does nothing. The update has been tried by downloading file to computer and straight to the TomTom. TomTom MyDrive Connect does not see the unit. Not sure if unit is supposed to be seen by windows explorer as a drive, but it is not.
Any ideas on what is going on would be much appreciated.