I recently built a new computer, and everything is working perfectly fine, except for the top USB port on the case.
The two cables that connect the front USB ports to the motherboard come together at one header, which is plugged into the USB socket on the motherboard.
The bottom port works fine, but the top does not.
I have tried it in the other sockets on the motherboard, with no change. When I plug anything into the top one, the led will come on for a second or so, as though it will work, but it will go off, and windows will report device driver not installed, device not working.
What could be the source of this problem? The cable looks fine, and so does the header.