Same thing happened to me - you have to roll back your USB 3.0 drivers in order to have windows detect anything plugged into them.
In my case detection was not a problem. My controls were acting crazy, input lag, stuck directions etc, and I got ally crappy performance from my rift, including the greyouts. If I played in 2D, my FPS was locked on 144 (limited by g-sync). No detection would have saved me a hell lot of reinstalling, tweaking, and banging my head to the wall