Make sure your cable is OK.
1: Make sure you don't have any damaged pins on the plug on your camera and on your USB port on the computer
Try using a different cable to be sure that is not the problem.
If you can t ry a different camera on the same cable and make it work, your camera is at fault.
Try it on a different USB port, and possibly also on a different computer to make sure the port on your computer is not at fault.
Check both cable ends and the ports on the camera and computer are not dirty