Windows only: Free program Process Explorer, by the good people at Sysinternals, is a Windows Task Manager replacement tool with all kinds of added functionality. 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 can be a great tool for
![Download of the Day: Process Explorer](https://cdn-ak-scissors.b.st-hatena.com/image/square/d7e6a6f5469cad912e746d908411e51ca810f9c1/height=288;version=1;width=512/https%3A%2F%2Fx.kinja-static.com%2Fassets%2Fimages%2Flogos%2Fplaceholders%2Flifehacker.png)