Q: BOOTCAMP ERROR MESSAGE: NO BOOTABLE DEVICE - INSERT BOOT DISC AND PRESS ANY KEY

Are you using your Optical drive to install Windows? Was Bootcamp Info.plist modified?

From System requirements to install Windows on your Mac via Boot Camp - Apple Support

MacBook Pro

Are you downloading drivers using Bootcamp Assistant?

You already have a USB2.0 with BC drivers and a physical DVD that you are using in your built-in Optical drive. Unless the physical DVD media is bad, if you are getting a black screen, the DVD may have been burnt at a rate not supported by the media. If your installer starts and your keyboard/mouse do not work, it is a USB/BC Drivers issue. If the Installer does not start, then it is the DVD media.

Are you trying to copy the DVD to the USB to try and boot from the USB?

On your Mac, you cannot install Windows from the USB. You must use the DVD and USB, both.

The USB contains (or should contain) only the BC drivers, it should not contain the ISO or the DVD contents, otherwise it will fail.

Do you currently have a W7 ISO image? If yes, You can use Disk Utility 12.x: Burn a disk image to a CD or DVD.

Do you get an error when you try to burn the DVD?