As TASKKILL might be unavailable on some Home/basic editions of windows here some alternatives:
TSKILL processName
or
TSKILL PID
Have on mind that processName should not have the .exe suffix and is limited to 18 characters.
Another option is WMIC :
wmic Path win32_process Where "Caption Like 'MyProcess%.exe'" Call Terminate
wmic offer even more flexibility than taskkill with its SQL-like matchers .With wmic Path win32_process get you can see the available fileds you can filter (and % can be used as a wildcard).