Getting vert. black borders on wide screen TV when in stream video (1 Viewer)

[symporter]

Hi everyone!

here is my problem i use MP to watch streaming TV over the internet and no matter what resolution I choose for my second TV/monitor the tv picture is always 4:3!!! Blue screen of MP is perfectly fine full screen (16:9)
TV, of course doesn't alow me to change aspect zoom in PC mode

Any ideas?

Thanks a lot!!!