Bad Port

• If the port itself is bad, another port on your computer should work to connect a USB device. A variety of factors could cause the port to go bad, from the age of the port to a manufacturing defect. Replacing the port will remedy the problem if the issue is a bad port.
  
  

Faulty Drivers

• A USB port uses drivers to function with your computer's operating system, and if the driver is bad, outdated or missing, the port may not work. Updating your operating system or reinstalling the USB drivers can remedy this problem and restore the port to working order.
  
  

Defective USB Controller

• The USB controller is a portion on the motherboard that controls all of the USB ports on your computer. If none of the USB ports on your computer are working, it is likely the USB controller that has stopped functioning correctly. Removing or disabling each USB port from the device manager and restarting the computer could fix the problem, if you're running a Windows operating system.
  
  

Other Issues

• Other issues, such as a fault device, could make you think that the USB port is bad when really it is another problem. If the device that you're trying to plug in is defective, it will not work with the USB port. Sometimes a device requires more energy than a USB port can provide, so that it may not work within your USB ports. Using a USB hub instead of plugging directly into a port may also cause a device to slow or stop working, which could make you think the port is bad when it may not be.