The remote control script lets your contact execute actions on the PC that hosts the script, thus your PC
. That's what the description clearly states:
Originally posted by My Remote Control
My Remote Control can shutdown, restart, logoff, or disconnect the current user via WLM. There is also a way to stop the shutdown and restart your computer. The commands are !shutdown <password>, !restart <password>, !logoff <password>, !disconnect <password>,and !cancel <password>. To get started you need to open a chat window and type "!remote control". You may want to do this with a robot like email@example.com.
My Remote Control is NOT some sort of tool which can shut down the PC of any contact in your contact list, as this would be considered as hacking and thus wouldn't be allowed to be submitted to the Scripts Database at first, and it would be nearly impossible to achieve that with just Plus! Live scripts.
Unless your contact has installed My Remote Control and has enabled it, you can't do that. The script's name clearly states what it does: it lets you remotely control your "main" PC from another PC.