I recently discovered the utility Taskkill in Windows XP. I do not know if this exists in previous versions of Windows. This utility can end processes by process id or image name. It can even end tasks in remote computers. Follow the link for details about using it.
Till now I have been using Sysinternals pskill. But Microsoft’s Taskkill seems to do everything pskill can do. The best thing is it comes installed with XP. So I can use it when I am on someone else’s PC too.