Using Task Manager
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The latest version of this topic can be found at Using Task Manager.
One of the simplest ways to debug a service is through the use of the Task Manager in Windows NT 4.0 or Windows 2000. While the service is running, start the Task Manager and click the Processes tab. Right-click the name of the EXE and then click Debug. This launches Visual C++ attached to that running process. Now, click Break on the Debug menu to allow you to set breakpoints in your code. Click Run to run to your selected breakpoints.