to shutdown a computer, if you are running on windows, you could use something like SSH, in linux you can conect to another terminal of you LAN, if you know the ipīs an the user/password, try to do it.....


*.-go to terminal
2.-log like root
*.-type this...."ssh login@ipadress" (ssh sirgrifin@**2.*68.*.64) hit enter.
4.- its going to ask you for the password, you have to type it and hit enter again, now you are conected with this pc in a terminal via telnet.
5.- now you are conected via telnet for some port i dont remeber, now log like root on this computer, using "su" and type the pass the same u use to get into this computer...
6.- to shouting down you just comands like "halt" "shut down now" "reeboot" things like this and by this way u can do it.

well about windows there are a lot of programs you can install on you pc, in you LAN, and run it knowing the ips and enjoy you damn free time shuting down computers.....