I have the Gigabyte Z77X-UD3H mobo. I do not understand why this is happening and why now, but the 2 rear USB 3.0 ports above the LAN port are not working. Anything I plug into them does not register. All the other USB ports work perfectly fine. It is just these two that are next to the SATA ports that are giving me issues. Does anyone have an explanation or a solution??
check in the bios that all your usb ports and devices are turned on. check that the usb drivers are installed. some mb use a third party chipset for some of the ports.