I just tested installing the latest USB 3.0 extensible driver 184.108.40.206 for Windows 7 64 bit. I had no problems while installing the driver with same NUC model.
It seems to be a problem with your windows registry. You could try running system restore System Restore - Microsoft Windows or re install windows 7 on your computer.
Finally I get the answer ................and conform it was worked.....
Ok, if you are unable to install the USB3.0, please check the BIOS, under USB setting whether the xhci is "enable" or "smart auto".
if xhci is disable, you are only allowed for using it as USB2.0
Hope it can help others....