If you're trying to kill a process in C# and getting an "Access Denied" error, it may be because you don't have the necessary permissions to terminate the process. To overcome this, you can try the following options:

Run your application with administrative privileges: This will allow your application to access and kill any process running on the system. To do this, you can right-click on your application's executable and select "Run as administrator".

Use the Process.Kill() method with taskkill: Instead of calling the Kill() method directly on the Process object, you can use the taskkill command-line tool to kill the process. This tool has administrative privileges by default, so it can terminate processes even if you don't have the necessary permissions. Here's an example of how you can use it in C#: 

This code gets all running processes with the same name as the process name specified, and then uses the taskkill command to kill the process with the specified process ID (/pid {process.Id}). The /f flag tells taskkill to force the process to terminate.

Note that using taskkill to kill a process may cause data loss or other issues, so use this code with caution. Also, be sure to handle any exceptions that may occur when calling Process.Start() to avoid crashing your application.