Copied from Process Explorer:
Ever wondered which program has a particular file or directory open? 
Now you can find out. Process Explorer shows you information about which handles and DLLs processes
have opened or loaded.
The Process Explorer display consists of two sub-windows. 
The top window 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
Process Explorer is in: if it is in handle mode you ll see the handles that the process selected in
the top window has opened; if Process Explorer is in DLL mode you ll see the DLLs and memory-mapped
files that the process has loaded. Process Explorer also has a powerful search capability that will
quickly show you which processes have particular handles opened or DLLs loaded.
The unique capabilities of Process Explorer make it useful for tracking down DLL-version problems
or handle leaks, and provide insight into the way Windows and applications work.
Changelog:
This update fixes a bug where the history graph tooltips could display the wrong data point and
reduces the memory footprint of the structures that store graph history.