issue re installing windows 10

so im using winusb to make my exteal hard drive bootable and when i go to boot to it, windows just tells me that there is no operating system found, im not sure why this is happening, ive tried a few different things now, I tried unetbootin and all my different usb ports, nothing seems to be working, and now i cant boot back into ubuntu because its telling me that i need to select a proper boot device.

motherboard - gigabyte ga-970 gaming

was ruing ubuntu 14.04 lts