A couple months ago I posted the same thing here, but I couldn´t solve my problem, so I decided to ask here. My 780 has a weird problem. When I try to load my system, the monitor shows stuff fine, but when it finishes loading the windows screen, the connection between the video card and the monitor stops. However, if I just enter on my BIOS and leave without doing nothing it works fine.
I actually switched the power supply, tried to change the input on the board ( DVI/HDMI) but nothing happened.
sorry if I misspelled anything, hope you understand what I´m trying to say.
Weird. Uninstall the drivers and than start windows in safe mode and use driver sweeper to completely remove them, after that restart your PC and let it boot like normal. Go to the nvidia website and download the latest beta drivers and install them. Restart your PC and see if everything works fine. If this doesn't work make sure to post a list of things you did try so we rule them out. The above protocol is a standard procedure in cases like yours. Hope this solves your issue.
I actually had to take off my gpu a few times because I let my BIOS settings to boot throught the PCIE
However, I noticed one thing: When I let it boot normally, I believe that after the "starting windows" screen, it´s not just the connection that stops, but it really doesn´t load windows. And before I installed the drivers, it boots normally throught the GPU.