Como faço para enviar uma mensagem para um usuário específico em um domínio do Windows 7?
Sending and receiving Net Send messages in Windows 8/7/Vista
In order to send or receive Net Send messages on Windows versions that don't support Net Send command (Windows 7, Vista, ME, 95, 98) you can use third party software products. We suggest using Winsent Messenger, Winsent Innocenti and Sent utility.
Winsent Messenger is a messenger for LAN, compatible with net send. Winsent Innocenti is a pared-down version of the Winsent Messenger, only allowing message receiving. Sent is a console utility intended for sending messages from command line.
The following are step by step instructions on how to add NET SEND support to Windows 7:
Download and install Winsent Messenger or Winsent Innocenti on all computers that should be used for message receiving (Go to the download page).
Download and install Sent utility and Winsent Messenger on all computers that should be used for message sending (Go to the download page)
Change Windows system settings according to the requirements on all the computer where you installed Winsent Messenger, Winsent Innocenti and Sent.
Now you can send and receive NET SEND messages on Windows 7. If you need to send the message from command line then type the sent command in a command prompt, otherwise use Winsent Messenger.
Fonte Como enviar e receber mensagens de envio de rede no Windows 8/7 / Vista