Not letting me boot from usb

I have built a pc and want to install windows 7 OS onto my pc I have a gigabyte h81m-h motherboard it's uefi bios and I have windows 7 on my usb and when I boot pc just says please insert w.e to boot from
.. I have changed the boot order still doesent boot from it any help guys ?

You can use Rufus to copy ISO file to flash drive to create a proper boot device. https://rufus.akeo.ie/
Chances are that the BIOS cannot read the install file because it is not configured properly.

Thanks .. But surly it would of worked when I went on the Microsoft web page and got windows ISO file and used there programme which puts IT on usb? And still dident read

Windows 7 USB download tool didn't work well for me too. That's why I have always used rufus for all my install sessions. It's easier and way more effective.

The other thing that Rufus will do is make sure that the the USB Drive is set to the right file system type. Which from memory should be FAT (but don't quote me there)