Command prompt

Shutdown Your Computer or a Remote PC via Command Prompt
Hibernate a Local Computer
Type in "Rundll32.exe Powrprof.dll,SetSuspendState" without the quotes and press Enter. Your computer should hibernate, if it does not, then you must enable hibernation to do this.
Restart your Local Computer
Type "shutdown -r" in the command prompt and press Enter. In this case, the command switch -r is telling the computer to restart after shutdown.
Log Off the Current User
Type "shutdown -l" in the command prompt and press Enter. The -l command switch tells the computer to log off.
Shutdown a Remote Computer
Type "shutdown -s -m \\name of the computer" in the command prompt and press Enter. Replace \\name of the computer with the actual name of the remote computer you are trying to shutdown. As mentioned earlier, you must have administrative access to the computer you are trying to shutdown. To know if you have administrative access, press Windows key + R and then type the name of the computer and press Enter.
Shutdown your or a remote computer after a specific time
Type "shutdown -s -t 60" to shutdown your computer after 60 seconds. Upon executing this, a countdown timer displaying a warning message will be shown. This command uses the -t command switch followed by a variable (which is 60 in this case) which represents the number of seconds after which the computer will shutdown.
Display a Message containing the reason for shutdown
Type shutdown -s  -t 500 -c "I am tired. I don't want to work anymore." (with the quotes) in the Command Prompt and press Enter. The -c switch is used in the code to give the reason for shutting down and what is followed in quotes will be displayed in the dialog box as the reason. This can be used to display all sorts of funny messages.  
Stop a System Shutdown
Type "shutdown -a" and press Enter. This will stop the system from shutting down if the countdown to shut down has not reached 0

  Know if your neighbours are stealing your WiFi connection

Command Prompt can let you know if someone is connected to your Local Area Connection and using it. Just follow the steps:-
1) Open your browser and visit http://192.168.1.1 or http://192.168.0.1 depending on your router.
2) Find the tab that mentions “Attached Devices” or something similar.
3) Find the computer name, IP address and MAC Address (sometimes called Physical Address or Hardware Address) of your computer using the previous trick.
4 )Compare it with those displayed by your router in Step 2. If you notice some strange devices, then your neighbour has been sneaking in on your internet connection and it is best to add a password.
Know if someone is hacking your computer/ Trace a Hacker

Want to know if someone is hacking your computer? Command Prompt can help you find if someone you don't know is connected to your computer stealing private data. Just execute netstat -a and the command prompt will return a list of computers that your computer is connected to. In the results returned, Proto column gives the type of data transmission taking place (TCP or UDP) , Local address column gives the port with which your computer is connected to an external computer and the Foreign Address column gives the external computer you are connected to along with the port being used for the connection. State gives the state of the connection (whether a connection is actually established, or waiting for transmission or is “Timed Out”).
....Directory,full colon then press Enter key.attrib -s -h -r /s /d then press under and recover hidden files.