Although possible, it'd be pretty rare for two cards to be defective in the same exact way.
What outputs are you using?
DP
What cables?DP cables that came with my moinitor
Tried different outputs and cables and/or adapters? What monitors are you using? Do you have a different model monitor to try to connect to?
Tried using HDMI and i have 2 Samsung S27A750D's. They both work perfectly using onboard gfx
If you can login it might be possible to install the nvidia drivers from the startup with some kinda quiet/unattented install command line options - bit of a stretch tho.
I can log in fine, the rest of that sentence i have no idea about

Do they work on there own in Safe Mode?
nope
