Windows Instillation

Hey guys, So I got my parts in, built my PC and everything works together. My problem was installing Windows 7 in. I don't have a CD drive. I do have an OS Disc. I managed to download an ISO file which is the same as the disc I have. I transfered it to a flash drive using the Downloader Tool. I then plugged it in, it loaded up, I clicked on install now and it said "No driver found" I don't really understand this? Anyone know a solution? I have a 1TB Seagate HDD. ASRock 970 Extreme3 motherboard. I am using my GPU for display. (R7870)

Thanks! 

 

EDIT: I solved it. Just had to remove the USB, go back to install now option and insert it to USB 2.0  and NOT USB 3.0. 

Are you useing a usb port on the motherboard instead of the ones on the case or a add on card?

I'm connecting it directly onto the motherboard. There are USBs in the case, but I would figure it should be directly into the motherboard.