The device has either stopped responding or has been disconnected

I tried to copy music files from my laptop PC to my phone, and it charges, the PC recognizes it and it appears in the portable devices tab but when I open it it's empty, showing 0 elements. When I try to drag anything I get that message.

Hi, when you connect the phone to the laptop does it automatically try and install the driver? have you allowed this process to happen first? secondly on the phone do you select file transfer when it's connected to the pc?