fs9 is crashing

hi, every time i fly the pmdg i make it to my destination airport, then when i am taxiing to the terminal i hear the windows 'ding' then all of the overhead buttons go missing 'file, edit, help etc.' except for modules and pmdg. I cannot exit fs9 after this happens, i just get the windows 'ding' and i cannot do ctrl alt delete either; i get the ding for that aswell. The fs9 update doesnt help.Help!__Alex