Today I bought a Samsung Syncmaster S24B150 (with 1 DVI and 1 VGA port), my Windows 7 desktop (Dell XPS 8500) has a Radeon AMD 7850 graphical card with 1 HDMI and 1 DVI port, I'm using a newly bought König CABLE-193/3 DVI-D 24+1pin male to DVI-D 24+1pin male.
My second screen (the samsung synmaster, DVI connected) does not show anything.
When I let windows detect my displays, it succesfuly finds the monitor:
I can also succesfuly make screenshots ranging both screens.
When I connect the samsung syncmaster via VGA to my laptop the screen works as should.
When I unplug the HDMI monitor, I still don't get anything on my DVI monitor.