Spy++ (SPYXX.EXE) is a Win32-based utility, included in 
Microsoft Visual Studio , that gives you a graphical view of the system’s processes, threads, windows, and window messages.
SpyStudio is the best product to trace user-mode API calls on Windows. SpyStudio is an Application tracer which shows and interprets calls, displaying the results in a structured way which is easy for any IT professional to understand.
API Monitor is a Windows program that lets you monitor and control API calls made by applications and services. Its a powerful tool for seeing how applications and services work or for tracking down problems that you have in your own applications.
The Sysinternals Troubleshooting Utilities have been rolled up into a single Suite of tools. This file contains the individual troubleshooting tools and help files. It does not contain non-troubleshooting tools like the BSOD Screen Saver or NotMyFault.
A free, powerful, multi-purpose tool that helps you monitor system resources, debug software and detect malware.
