An essential element in any local network (LAN) that is composed of several computers is that they can send messages to each other, so that they can communicate continuously.
And for this there is NetSender XP, a very basic and simple program, where you only have to write the message and select the computer to which you want to send it, that simple and fast.
For programmers it is of interest that on the author's website you have the source code of how this program is made available.
This version only works for Windows XP, if you have Windows NT or 2000 then you must download NetSender NT.
You can free download NetSender XP and safe install the latest trial or new full version for Windows 10 (x32, 64 bit, 86) from the official site.
Devices: Desktop PC, Laptop (ASUS, HP, DELL, Acer, Lenovo, MSI), Ultrabook
OS: Professional, Enterprise, Education, Home Edition, versions: 1507, 1511, 1607, 1703, 1709, 1803, 1809