I am running Windows 7 64 bit and when plug in the USB to the 5DMkll and connect to my computer I get 'Device not recognized' I am using the latest EOS Utility software and the latest firmware.
Is there a separate device driver for the 5D?

I can't answer your question because I have never plugged the camera into the computer. It is more convenient and faster to use a card reader to get files into the computer. The card reader is always there from bootup and I don't have to take the camera out of the bag to load video.