@ echo off
:A
Cls
echo MESSENGER
set /p n=User:
set /p m=Message:
net send %n% %m%
Pause
Goto A

now click on file
click on save as
and then give it the name messenger.bat
click save

now goto control panel
click on administrative tools(switch to classic view)
then click on services
then find messenger service
open it
you'll see startup type which would be disabled
so click on that and select manual
now press the start button and apply

now do the same on the remote computer
until this service is activated on that pc, you won't be able to use this

now click on that file you made
type the ip
type the message
and enter

there you go!