The program that comes to mind for me is the one called Process Hacker (it's just an advanced Task Manager). Within its configuration settings you can set it up to see all/children processes of active processes in use. In the "Description" tab of the Processes' windows, you will see a brief description of the program running and if a file is in use, you will see a drop-down arrow next to said item to see the file in use. As well as an incredibly detailed instant pop windows providing many other details such as the directory of said files.
