It would be helpful to understand your application a bit more. The WinXP command that does this is taskkill.
http://www.tech-recipes.com/rx/446/xp_kill_windows_process_command_line_taskkill/

On my XP machine >taskkill /? gives a lot of help

In general "killing" another process is a very dangerous thing to do as this can leave corrupted files, etc. The normal way that this is done is via signals which is sort of a very simple message that just says: hey, shut yourself down". The program that you want to shut down has to have code that understands and does something with this signal. But, yes you can do anything that you could do yourself via a Perl program.

Update: I played around with this a bit. It appears to work completely "as advertised". There appears to be a "polite signal" and also the /F option which I figure is like unix kill -9 PID, "you are gone".

C:\Projects>notepad
C:\Projects>taskkill /IM notepad.exe
SUCCESS: The process "notepad.exe" with PID 5456 has been terminated.
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