If you have made any changes to the USB settings in BIOS, revert those and retest. If you are using a USB hub, remove and retest by connecting devices directly to USB ports. Proceed to next step if none of these apply.
Visit the support page for your rev board 1.0 or 1.1...
http://www.gigabyte.us/Motherboard/GA-Z77X-D3H-rev-10#support-dlDownload both the Intel and VIA USB drivers for your board. Keep in a safe place.
Next visit Device Manager. Expand Universal Serial Bus Controllers heading and look for errors. yellow triangles, red exclamation point, red X's, etc. Take corrective action if necessary... re-enable device if disabled, determine root cause, missing drivers, Code 10 cannot start, etc...
If only one entry has an issue... right-click on it and select uninstall... leave the box to remove all drivers for the device un-checked and restart the system. The device should reinstall automatically. Now retest.
If all of the devices appear to be installed and working....
Right-click and uninstall each entry, select the remove device drivers for each device check box. When all the entries under USB heading have been removed, close DM and restart. The devices will be re-detected when the system restarts. Close and ignore the dialogs prompting to install drivers.
Now run the USB installers from above one at a time, rebooting between each. Check DM and confirm all devices under USB have installed correctly. Retest.
