Hi Newmann,
Did you ever get this resolved? I am having the same problem with my Dell Precision 7730. I have even ordered a TobenOne that is supposed to automatically support up to 3 external monitors but I cannot get windows to recognize my 2nd external monitor. I am using 2 different 32" monitors but only 1 will work.
When I connect them both to the TobenOne docking station none of the external monitors will work. Was there a particular download you found that resolved your problem? I am hopeful you found a solution because no one has responded to my post of this very similar problem. I know both monitors will work on my HP i-7 laptop but it has a faulty motherboard, so that is why I switched to the Dell laptop. I am stumped as to why the Dell laptop will not work and quite honestly very frustrated.
The Hp was running to the HDMI port and an adapter through the USB 2.0 port with no problem, so I know the setup should work on the Dell. Still nothing that I have tried will work and I am becoming very annoyed with the situation. I did not have a situation where the Dell was working and then stop working after an update. The Dell has never worked with both monitors at any point when I tried to run it.
My graphics card on the Dell is the NVIDIA Quadro P4200 and I am not sure that matters. Thank you for any reply to this message.