PCI-E video card not displaying

[invisiblestupid]

Hello, I'm new to Mint and Linux in general. I've been experimenting with Mint Mate for a few weeks now and so far I like it but I'm having trouble. I have two monitors connected to my onboard video and have a third monitor that I need to connect to an external (pci-e) card. I just cannot get Mint to see the third monitor. I've tried quite a few combinations of pci-e cards and monitors trying to get something to work but so far no dice. My desired config is an MSI N520GT card (NVidia GeForce GT 520) and my Dell monitor. But when I couldn't get that to work, I tried other combinations including an old GeForce 6600 and really old Viewsonic 17". No combination works. I did notice when I go to System Information -> Devices I see an entry for "VGA compatible controller" NVIDIA Corporation NV43 [GeForce 6600] (rev a2) and so on...but nothing shows up in Monitor Preferences. Any ideas? What am I missing?

[grimdestripador]

Last time I got three monitors working from 2 different cards all from one desktop session, I had to edit text files. I don't know of any GUI tool to do this. This is not trivial.

[invisiblestupid]

I'm not opposed to editing text files if I knew what to edit where. Any thoughts?

[grimdestripador]

First, you need to have the nvidia driver installed if you don't, please install.

In a veague rememebrance. It went somethign like:

Connect up Monitor 1.
Use 'sudo nvidia-settings' to 'save to x configuration file' and save it in your home for reference as ~/xorg1.conf
Shutdown. Connect Monitor 2 to Port 2. Bootup.
Use 'sudo nvidia-settings' to 'save as' the configuration. and save it xorg2.conf
Shutdown. Connect Monitor 3 to Port 3. Bootup.
Use 'sudo nvidia-settings' to 'save as' the configuration. and save it xorg3.conf
Manually Combine the information for each of ~/xorg files.
backup a working copy of the /etc/X11/xorg.conf
save the super modified xorg file as /etc/X11/xorg.conf

You also might get luck with using nvidia-settings with all three montors after you correctly configure them. In my experiance from Xorg (was actually xfree86? then), is a picky creature and manually editing is hard.