"AMD R9 380 and Intel Core i3 6100 "
When you add a PCIe graphics controller (AMD R9 380) to your motherboard, the BIOS usually disables the integrated graphics controller when the graphics option is set to 'Auto'. So, it makes sense in that scenario that the Intel Driver Utility cannot find a driver for your graphics controller, since it's AMD.
If that is the case, try this driver: http://support.amd.com/en-us/download/desktop?os=Windows+8.1+-+64
In regards to your inquiry about the installation of the Intel® graphics driver, I just wanted to confirm if the previous information was useful for you and now the driver got installed and the PC is working properly, or do you still have the same problem?
Also, since you are using the AMD R9 380 video card, the onboard video gets disable when you use a video card, because of that the graphics of the processor are not being used, everything related to graphics in this case will be supported by the video card itself, so, the driver for graphics should be provided by the manufacturer of the video card in this case AMD.
Here you have a link where you can find the drivers for ADM video cards: