I have tried to connect my new S4 to my pc using the usb cable supplied with the phone. When I plug it in the pone beeps, however there is no activity on the pc and looking at the my computer screen, the phone does not show up. Also in reading about this function I saw that the phone is supposed to show a notification at the top of the screen, this does not happen either. What if anything am I doing wrong? Is there a setting that I am missing? Thanks in advance for any and all help.