Final answer:
The tool that is not included in Windows 10 for troubleshooting a user's computer is Message Analyzer.
Step-by-step explanation:
The tool that is not included in Windows 10 for troubleshooting a user's computer is Message Analyzer. Windows 10 does include the other three tools: Reliability History, Event Viewer, and Task Manager.
Reliability History provides an overview of system stability and reliability, displaying any failures, warnings, or crashes. Event Viewer records and displays system events such as system errors, warnings, and notifications. Task Manager allows you to monitor and manage running processes, system performance, and startup programs.