Process Explorer is part of sysinternals and is an advanced process management utility that picks up where Task Manager leaves off. It will show you detailed information about a process including its icon, command-line, full image path, memory statistics, user account, security attributes, and more. When you zoom in on a particular process you can list the DLLs it has loaded or the operating system resource handles it has open. A search capability enables you to track down a process that has a resource opened, such as a file, directory or Registry key, or to view the list of processes that have a DLL loaded.
The Process Explorer 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, which you can close, depends on the mode that Process Explorer is in: if it is in handle mode you will see the handles that the process selected in the top window has opened; if Process Explorer is in DLL mode you will 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.
Process Monitor is part of sysinternals and is an advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. It combines the features of two legacy Sysinternals utilities, Filemon and Regmon, and adds an extensive list of enhancements including rich and non-destructive filtering, comprehensive event properties such session IDs and user names, reliable process information, full thread stacks with integrated symbol support for each operation, simultaneous logging to a file, and much more. Its uniquely powerful features will make Process Monitor a core utility in your system troubleshooting and malware hunting toolkit.
Executing Process Monitor requires local Administrative group membership. When you launch Process Monitor it immediately starts monitoring three classes of operation: file system, Registry and process. Check the Sysinternals site for more details.