PSkill is part of Microsoft’s Sysinternals collection of free tools.
You can get PSKill as a part of PsTools collection from here.
To use pskill you either have to be in DOS command (cmd) window or download and install PowerShell.
Usage: pskill [-t] [\\computer [-u username [-p password]]] <process ID | name>
-t      Kill the process and its descendants.
-u     [...]