Loading TT5 problem

I have the Mitac Mio 168 with TT5 all was well until yesterday when after running 3 trips I turned on and selected Tomtom. The small icon appeared in the lower right hand corner then froze up. After pressing the reset button the mitac fired up but the same happened.Having tried this for a further 4 times I gave up went to the garage and bought a map. End of problem (short term). On arriving home I tried again same outcome.This called for drastic measures so switched of on back to carry out full restart. The windows side worked straight away but then when I continued to load TT5 I get as far as select voice. Here is where all goes to rats. The moment you hit the select icon it turns black and freezes. I tried the other voice option , same outcome!!!

Having had more freezes than a Sibirian winter I am starting to lose faith in what has been for six weeks an excellent piece of kit. If anyone has any ideas I would be greatful.

Chip.