Disabled Intel HD4600 on my new PC and display went black?

[windspeed36]

There are a number of things that could cause this so we'll start with physical issues. Have you ensure that the card is seated correctly, power connected and the monitor is plugged into the graphics card, not the motherboard?

If you've done those and you're still having issues, clear the CMOS. To do this refer to your motherboards manual however the easiest way I've found is that some boards have a switch to do so.