when switched on goes straight to language set up?

when i switch my TomTom it starts of on the language log in,then i go through to all the select set up until i come to the select the voice it will not let me go past the select button after it has been selected the select light dims as it is going to on to the next set up but after a while the screen goes back to start up then switch off, it will come back on its own then goes to the language set again. this tomtom has been working ok till i went to down load a tomtom update. please could you advise

many thanks

it is a tomtom one, serial no pb416g067748ee.13.00

barry jones
September 2010