2nd video card not detected

[tServo]

I just went thru a frustrating hardware debugging session and discovered something that may save someone else's time.

I replaced a rather modest video card in a I7-8700k system with a nice, new Nvidia board.
I went thru the usual steps and all went smoothly. I noticed something when I ran Afterburner that later proved to be a problem: the built-in Intel graphics showed up as a video device.
After running lots of tests I was satisfied all was ok and then installed another of the same board.
When I rebooted, the second board was nowhere to be seen, either in the device manager ( this is a Windoze 10 machine ) or Afterburner.
There were no loose/bad connections so I tried to disable that second, Intel video device on a hunch. The machine's bios would not allow that.
What fixed it was to uninstall the NVidia driver and re-install it. Then all was well.
BTW, I was using the latest drivers available.
I hope this saves someone some time.