If the headset mic doesn't work with this PC even after you try the USB audio adapter, this points to a failed mic. Try it on another PC then get the headset exchanged.
I have windows 10 in a custom PC that I recently built. My headset/audio input/output is the 'Razer Kraken 7.1' which has a built in mic that I can confirm does work as I use it often on various other devices. I have tried everything to get the mic to work. I have uninstalled and reinstalled drivers and got nothing. I have configured every setting possible on the 'Manage Audio Devices' window. I have purchased an audio splitter AND a USB audio adapter. I APPRECIATE ANY FEEDBACK AND I HOPE I CAN GET IT WORKING AS SOON AS POSSIBLE.