1. Firstly on your pc.
2.press the the startup menu and search for the command prompt.
3.it will bring out a black screen for you with a blinking cursor
now to  shutdown your pc simply press shutdown/s  
to restart your pc type shutdown/r
to log off your pc type shutdown/l
to exist the command prompt simply type exist
for more options type shutdown/?
  command prompt is not a kid tool to be toy with. be extremely careful when you are using it.