well, for the shortcut trick to work, you may need to have an administrative account on the target machine with a username and password that matches one on the machine you're using.
Never the less, to cretae shuch a shortut, just rightclick on the desktop and select "new"->"shortcut"
when prompted for the shortcut path, write out the command in full.
to run the shorcut as an administrative account, right click on it, click on the shortcut tab, and click the "advanced" button. Check the "run with different credentials box, hit ok, and then hit apply and ok on the shortcut tab.
Each time you rightclick the shortcut from then on you will have the option to "Run As...". Select this option, choose the administrative account which you would like to run it with, enter the password, and away it runs.
As for the precise command, I've forgotten whether I used tsshutdn or shutdown myself, but if you're having trouble knowing which to use and with which switches, I'll fire up my second machine and get it for you