I have to Shut Down a computer under a same local area connection of my computer,how can I do this?

Go to
"Start"
"Turn Off Computer"
"Turn Off"

and it will shut down and so will your local area connection.

goto command prompt
type: shutdown -s -t 20 -m \\computername

-s - means shut down
-t 20 - means 20 second time delay
-m \\computername - the remote computer you want to shut down

yes, I tried it to many computers but it says access denied? tell me how can I do this??