Linking a picture from Laptop to Sony AV Amp??

Hi folks,
I want to link my laptop picture through my Sony AV amp (STR-DB940) so it displays on my tv (Tosh 42WH18). I have linked the source through video 3 and the sound comes through OK, however, I cannot seem to get a picture. If I link the laptop directly to the TV I can get the picture to display without a problem. I set it up by going to:-
Control Panels - Appearance and themes - change the screen resoultion - settings - advanced - nview display mode - device settings - select output device and from there simply selected TV mode PAL. I cannot seem to get it to work connecting it thorugh the AV amp. Can anybody guide me on how to this if possible.
Thanks in advance!!

 

Have you checked that that specific sound source is connected to the video output. I might be different to what you expect. Something to keep you going anyway...

 

Thanks for the quick response. I can get the sound working through the Amp without a problem, all leads are going into Video 3 in. I am sure the problem lies within the computer with regards to a setting I may not be doing correctley in order for it to output a picture signal, I maybe wrong though.