Using taskkill will help you with your issue.
The general syntax of the command looks like this:
taskkill [OPTIONS] [PID]
As you might expect, there are plenty of options available for this command. Some of the more helpful options are:
/s COMPUTER -- (Where COMPUTER is the IP or address of a remote computer). The default is the local computer, so if you're working with a command on the local machine, you do not have to use this option.
/u DOMAIN\USER -- (Where DOMAIN is the domain and USER is the username you authenticate to). This option allows you run taskkill with the account permissions of the specified USERNAME or DOMAIN\USERNAME.
/p -- If you use the /u option, you will also need to include the /p option, which allows you to specify the user password.
/fi -- Allows you to run the taskkill command with filters.
/f -- Forces the command to be terminated.
/IM -- Allows you to use an application name instead of the PID (Process ID number) of the application.
This can be seen on CMD by typing taskkill /?
Use the help switch for the taskkill command.
Killing with application name
The simplest way to kill a rogue application with taskkill is using the /IM option. This is done like so:
taskkill /IM APPLICATION_NAME
Where APPLICATION_NAME is the name of the application you want to kill. Say, for example, Outlook is refusing to close. To close this with taskkill, you would execute the command:
taskkill /IM outlook.exe
Hope this helps - good luck!