SHUTDOWN BY A SINGLE CLICK IN WINDOWS

right-click on an empty Desktop spot -> select New -> Shortcut -> type shutdown followed by a space, and then enter one or more of the parameters listed below -> click Next -> type a suggestive name for your new shortcut -> finally, click Finish.


This is the Shutdown.exe (located in %systemroot%\System32, usually C:\Windows\System32) syntax:

shutdown [-i|-l|-s|-r|-a] [-f] [-m \\computername] [-t xx] [-c "Text"] [-d[u][p]:xx:yy]>

Valid command line switches: 

-a = Abort system shutdown in progress ONLY IF the -t xx timeout option was already set to ANY value other than 0. ALL switches except -l and -m are ignored during abort.

-c "Text" = Text comment (case insensitive) to be displayed in the Message area of the System Shutdown window. MUST be enclosed between quotes. Maximum allowed 127 ASCII characters.

-d [u][p]:xx:yy = Reason code for shutdown:
u = User code.
p = Planned shutdown code.
xx = Major reason code. Positive integer number less than 256.
yy = Minor reason code. Positive integer number less than 65536.

-f = Force running applications to close without warning.

-i = Display the shutdown interface (GUI). MUST be the first option!

-l = Log off the current user of the local computer (default action). Can NOT be used with the -m option unless the current user has Sysadmin rights, in which case the -m switch takes precedence.
-m \\computername = Remote/network computer name (most always case sensitive) to log off/restart/shut down. Current user MUST have Sysadmin rights to be allowed to use this switch! 

-s = Shut down the local computer.

-r = Shut down and restart (reboot) the local computer.

-t xx = Set shutdown timer to timeout for xx seconds. IF NOT specified defaults to 20 seconds. Allowed values between 0 and 99 seconds. The -a switch is the ONLY one that CAN be used during the timeout period.

NOTE:
The dash (-) in front of these switches can be replaced by a forward slash (/).

Spaces are NOT required to separate the shutdown command from ANY following switches, but ARE required to separate ANY switch from its following parameter(s), if any.
For example: 

shutdown -s -c "Shutting down!" -t 3 
tells your computer to shutdown after waiting for 3 seconds while the System Shutdown window will display text above in the Message area.

Optional: after you're done creating your customized shortcut for shutdown -> right-click on it -> select Properties -> enter your desired key "combo" in the Shortcut Key box (e.g. Ctrl + Alt + End) -> click OK/Apply.  

From now on just left-click on your shutdown shortcut or hit that key combination to turn off/restart/log off your computer.