Sure you can kill processes but for some reason Firefox seems to leave threads hidden or just doesn't end properly sometime(I run FF 3.5.3 right now).
Thanks to a Twitter follower, Dims an IBMer who pointed me to this tool set from Microsoft.
PSkill is just one tool in the download. And it works remotely as well!
http://technet.microsoft.com/en-us/sysinternals/bb896683.aspx
PsKill v1.12 By Mark Russinovich
Published: December 4, 2006
Windows NT/2000 does not come with a command-line 'kill' utility. You can get one in the Windows NT or Win2K Resource Kit, but the kit's utility can only terminate processes on the local computer. PsKill is a kill utility that not only does what the Resource Kit's version does, but can also kill processes on remote systems. You don't even have to install a client on the target computer to use PsKill to terminate a remote process.
Installation
Just copy PsKill onto your executable path, and type pskill with command-line options defined below.
Using PsKill
Running PsKill with a process ID directs it to kill the process of that ID on the local computer. If you specify a process name PsKill will kill all processes that have that name.
Usage: pskill [- ] [-t] [\\computer [-u username] [-p password]]
- Displays the supported options.
-t Kill the process and its descendants.
\\computer Specifies the computer on which the process you want to terminate is executing. The remote computer must be accessible via the NT network neighborhood.
-u username If you want to kill a process on a remote system and the account you are executing in does not have administrative privileges on the remote system then you must login as an administrator using this command-line option. If you do not include the password with the -p option then PsKill will prompt you for the password without echoing your input to the display.
-p password This option lets you specify the login password on the command line so that you can use PsList from batch files. If you specify an account name and omit the -p option PsList prompts you interactively for a password.
process id Specifies the process ID of the process you want to kill.
process name Specifies the process name of the process or processes you want to kill.
See twitter is good for something.