Task Manager enables you to monitor the applications, processes, and services currently running on your computer. It also enables you to stop any programs or processes, as well as view how much of you computer resources (i.e. CPU, memory, etc...) an application or process is using.
To run Task Manager, go to the Start menu (the blue X in the lower left corner), then “Local Administration,” then “Task Manager.”
Video demonstrating how to open the Task Manager application and using it to stop a Firefox application process: