Data transfer problem

How to transfer photos and videos from iPhone-7 to windows-10 PC ?

I connect my iPhone-7 with windows-10 PC using lightning cable. When I try to copy folders like 100APPLE, 101APPLE, etc. to windows PC, it starts transferring files, but after some moment it generates an error Pop-up message "a connected device is not functioning" and when I press the "OK" button on this pop-up window, it stops data transfer and all the sub-folders in "DCIM" folder shows empty.

My iPhone's internal storage is full. So I badly need to transfer all the photos and videos that I took so far to an external storage device. Please help....