|You probably have a desktop computer. |
You need to disconnect the fifth wire for one port on the USB header on the mboard.
There are two standard uses for the fifth wire coming from one of the the case USB ports - or the fifth pin for one side of the mboard USB header - a second Ground, or Overcurrent. There is no problem if the fifth wire / fifth pin is used for the same thing on both the case USB port and the USB header, but if they are used for different purposes, you get the false overcurrent message from the mboard even when nothing is plugged into the port.
If there are individual wires from the case USB ports to each pin on the header, then just don't connect the fifth wire from the one USB port to the 5th pin for one of the ports on the header.
If you have a 4 in a row wiring connector for one USB port, a 5 in a row connector for the other one, install the 5 in a row one on the 4 pin side of the USB header so the fifth wire is where there is no pin, and the 4 in a row one on the 5 pin side of the header so the fifth pin is not connected.
If you have a one piece 2 port wiring connector from two ports, you will need to cut the fifth wire on one side of it, or bend the tangs flat that hold the metal end on the wire inside the connector inside the 5th wire's position, by inserting something small from the wire side to flatten the two tangs, such that the metal end will easily pull out of the connector.
See the mboard manual if you need to determine which pin is for what on the 5 pin side of the USB header.
The individual wires on wiring from front case USB ports is usually marked on the connectors. If there are two marked ground for a USB port, either of them can be connected to the 4th pins on the header. If one is marked Overcurrent, don't connect that to the fifth pin on the 5 pin side of the mboard USB header .