Download HandleEx from www.sysinternals.com.
Ever wondered which program has a particular file or directory open? Now you can find out. HandleEx is a GUI/device driver combination that together show you information about which handles and DLLs processes have opened or loaded. Its display consists of
two sub-windows. The top always shows a list of the currently active processes, including the names of their owning accounts, whereas the information displayed in the bottom window depends on the mode that HandleEx is in: if it is in handle mode you’ll
see the handles that the process selected in the top window has opened; if it is in DLL mode you’ll see the DLLs that the process has loaded. HandleEx also has a powerful search capability that will quickly show you which processes have particular
handles opened or DLLs loaded.