I cannot use usb devices on my bootcamp windows 7

I tried to install windows 7 ultimate on my mac pro retina late 2013 model and I cannot use the internet easily. So, I downloaded the windows supported software manually and copy to the flash drive. And then, I stated the bootcamp. Everything is fine and I successfully installed windows 7 but I want to install drivers for windows; such as graphics, camera, network card and so on. The problem is it doesn't recognize the usb. I can use keyboard and touchpad but I cannot use any usb devices. Thanks.