First go here www.youtube.com/watch?v=98xlSjTyCaQ and make the USB bootable(just follow the steps, even if you've already made it bootable before) once u make it bootable put the windows copy on there and make sure that that copy of windows is bootable because iv has instances where the copy of windows isn't bootable, then go into your bios and for the boot priority change it to HDD and make the USB the first in the list if your wondering why your setting the HDD first is because the flash drive is basically a mini HDD.
Now it should work, and if it doesn't try the USB on another computer to check if the copy of windows is bootable, it might not be so just go DL another one and put it on there.