english question

switch off the computer is correct
原因:switch off 是用於切斷(電流)等
For example:Switch off the gas,power,computer etc at the mains.
而close是指(某物)關;閉
For example:close a door,a window,the curtains,etc.

Neither close the computer or switch off the computer is correct. Cause the computer will shut down when you click the word 'shut down'=]

switch off the computer is right!

close the door,close the window!

turn off the fan!