You should download Nikon NX2 from the Nikon UK website, it is free to Nikon users, you then plug the SD card into you computer, or plug the camera in with a USB lead and it should automatically download your images, it can be set up to only download new images so you don't get repeats. The program will file them for you in a basic file, or you can choose your own. Also if you take RAW images which are better than jpegs you can edit the image quite comprehensively and convert the files you want to jpeg and save them where ever you want. It is also included in the disc that comes with the camera.
If you prefer photo shop you can still load the images from NX2.
Have you tried a different lead into your computer, and also use a different USB port just rule out any computer or lead faults.