Or, if you're able to add a program to these computers, it's fairly straight forward to make a Python script that will check a server and see if a specific command has been issued, and then act on that command. If you don't have a server, you could always just use email to communicate to your programs.
Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. -Rick Cook