Firstly, you need to connect your notebook to a LAN (local area network), if you want to use it locally, and to download and install a LAN messenger. You can try using tools like Softros LAN Messenger, Fomine LAN Chat or AChat. If you want to use it globally, you will need to connect the computer to Internet and to download and install a program from Software Informer database. Many of them are free of charge and easy to install and use. If you have problems, update your network card drivers.
Note: In both cases you need to make sure that your interlocutors are using the same application.
