I have a Dell Precision 390 with a QuadroFX 3450 gfx card. I installed the certified SW drivers. I dont see a setting in the control panel on making SolidWorks take up both screens. I remember seeing an icon years ago in the standard Window GUI next to the "X" button area that allowed you to choose what applications open or display on what screen.
Anyone have any tips on getting this working?
nVidia Desktop Manager / nVidia Window Manager
It may need to be turned on in the nVidia Control Panel.
Horizontal Span is the only way to make SW take up both, Dual View is a much better mode to run in.
I just came across this question, so I may be answering it a bit late, but the answer is....
When you install an Nvidia driver, in most cases you can turn on the Nvidia Nview Desktop Manager. This has to do with what driver you have installed and what OS you are running. Incidentally, since I moved to Win 7, my version of the driver does not have a Nview Desktop Manager, but I'm hoping it will in the future. Once you turn on the Nview Desktop Manager, there is an area that allows you to add those buttons next to the Red X. Possible buttons include the button to throw the app to the other screen, minimize the app to it's title bar, and also to have the app span both screens. One of the ways to turn on the desktop manager, would be to find the Nvidia icon in your system tray and you should see an option to get into the manager from there, it has to be turned on before you can use it. To see if it is installed already you right click on the desktop background and in addition to Nvidia Control Panel you also see Nview Desktop Manager in there.
Off the top of my head the only thing that rings a bell is setting your displays up in "horizontal span" this will stretch the screen across both monitors, I don't care for this setting due to the break in the middle.
Mine are set up in "dual view". for SW use the left monitor is my modeling space and the right I have the prop manager, command manager and file explorer, etc.
As for something in the windows GUI, I can't say I have ever seen that. There are some 3rd party programs that add that functionality though.