If you ever wanted to kill a process from the command line, there’s an easy way to do it.

First, show what processes are running using the tasklist command:

C:>tasklist

Second, use Taskkill to kill it by process name or process ID:

C:>Taskkill /IM firefox.exe /F

C:>Taskkill /PID 26356 /F

The /F flag forces the process to quit.

[Source: Tweaks]