try to see if you can locate the files in your phone, try to check memry status if it still has alot of free space in phone memry and memry..if there still alot then there's something wrong with the usb.. if your pc is an old version try uninstalling then re install again the usb drivers. if you cannot locate the files in your phone, you have to reformat ur memry, if that won't work reformat phone memry and memry