[NAME]  Let us know if clearing BIOS helps. BTW: Have you tried using HDMI(NVidia card)>HDMI(monitor), instead of DP>DP, when booting?
If I connect the DP cord to the NVIDIA video card on the system (lower position), the system won't boot up. If I connect it back to the upper port (which will only use Intel video card), the system can start. The photo on the back of my unit is attached.  [IMAGE] NVIDIA card works fine if the system is booted, in the Windows interface, I switch the connection from upper port to lower port, but the system won't boot up if it's connected to the lower one initially when I push the power button.  I made one change in BIOS which is the video-> primary display (thankfully I took a photo when made this change), I changed it to NVIDIA HD Graphics, it was originally Auto settings. This photo is attached. I guess this is the cause of this problem.  [IMAGE] Now I cannot go into BIOS, the screen is just black, the monitor shows amber, which means no video signal I guess? For now, is there a way I can rest BIOS settings through the Windows system interface? Or are there any other ways I can solve this? 
XPS 8940, Nvidia DP, no display, onboard works?