Process Explorer (free from Microsoft) shows information about running processes and loaded DLL’s. It is useful for tracking down DLL-version problems or handle leaks. It gives you much more information than the Windows Task Manager. You can even replace Windows Task Manager by Process Explorer. By rightclicking on a program or process name you start a search in Google (yes not Bing 
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Freeware suitable for Windows XP and higher
Popularity: 15%