remove all drivers, put the bios back to defalt settings, turn off the machine, plug monitor into the external graphics card, this should work as all external cards should overwrite onboard graphics, lemmi know how it goes. have some mo0re thaughts on this if it dosnt work, but its a matter of rulling things out first.
I have tried doing that, but still it doesn't work. I have tried to disable the onboard video from device manager and also change in BIOS to PRIMARY VIDEO ADAPTER: PCI-E, but still it doesn't work. I have properly seated the card into the PCI-E slot, but still