My iphone charges when connected to my computer but does not show up. How do I get it to show up so that I can access pictures and videos again?

I have an iphone 5c and when I conntect it to my laptop it does not show up in the drive list (Windows 7) so that I can select it and pull up any data or pictures on it like I was once able to do. It is connected and charges fine but does not allow access to the phone itself. How do I get it to show up again?