In CMD, use taskkill /IM "processname.exe" /F to forcibly terminate a process, replacing "processname.exe" with the actual process name. The /F parameter forces the command to stop the specified process. In PowerShell, the command Stop-Process -Name "processname" -Force achieves a similar outcome, with -Name specifying the process by name and -Force ensuring the process is terminated, providing a method to manage running processes effectively.