Are you trying to open Archicad (or any of its palettes) on the secondary monitor?
Archicad really doesn't like the Intel graphics cards.
Can you plug your second monitor into the GeForce card as well.
Or as an experiment, try disconnecting the second monitor temporarily and then start Archicad.
Also make sure you are not running the GeForce Experience software - This has caused trouble in the past.
Barry.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10