Close program remotely

Is this possible, I have written a program in XE2 which is run on three PC's, however when I need to update the program (its stored on a shared drive), i need to tell the program running on the other pc's to shut down. I am new to network programming so any assistance would be really appreciated.

You can broadcast UDP messages in specific port(s), and have your software listening to the UDP port(s) and take proper action upon receiving messages. Note that udp broadcasts usually only receivable by those in the same subnet, for gateways/routers usually automatically drop them.