You can now try and terminate the application process which in most cases offers immediate results.
- Click the tab "Processes" to load all active processes.
- Search for the .exe (executable) name for that software and click "End Process"
It is recommended to sort applications by using the memory column to see which ones have the most affect on your PC performance.
You will want to ensure your processes are clean and efficient when your PC boots up. You can do this by disabling startup applications!