GTX 470 need help

Hi all , I'have got a big problem with my geforce gtx 470 .I have just changed my pc : now I have an intel Core i7 extreme 980x,mobo X58-USB3 o.s. windows xp pro . I run Fs9 on two monitor very very well .When I run FsX ( golden edition ) if I choose a new window ( f.e. external observer ) everythinggo well if I run only a monitor . If I move the new window on the second monitorthe image of the window that I have moved have a very very bad quality impossible to see. If I return the window on the firstmonitor the image return normal . Many thanks for your help .Best regards Maurizio