If an application is causing your PC to slow down, it's likely consuming too many system resources. You can identify the culprit through the Task Manager (Ctrl + Shift + Esc), where you'll see CPU, memory, and disk usage. Look for processes using a high percentage of these resources. Once identified, you can try closing the application or restarting your PC to alleviate the slowdown. If the issue persists, consider updating the application or checking for compatibility issues with your operating system.