Assuming you have attempted to restart the install process, there could be many reasons for this, but three likely suspects are:
Devices in the NUC (external USB devices including keyboard and mouse), Wifi Card
Storage device (SSD/HDD)
Maybe try one thing at a time and see what is the culprit.
OK, I originally removed the SSD I purchased as the BIOS didn't detect it although Windows 8.1 did when installing. I replaced it with a traditional HDD but despite removing the wireless card I had installed Win 8.1 and Win 8.0 refused to install successfully. I finally installed win 7 professional SP1 but am plagued by problems still. I am beginning to think this NUC is a POS.