a simple batch file which shutsdown your computer in a given time

open notepad type shutdown -s -t 60
save it as shutdown.bat on desktop or where ever you like
this creates an icon like a setting file on desktop.
double click it and you are done your system will shutdown in 60 seconds surely.
you can change the time. dont forget that the time is in seconds

operating system

An operating system is the main thing which instructs the computer to work and it will make the hardware to work. A computer is a machine which can perform any work using variuos types of hardware which are instructed using some set of codes. All such group of codes collectively called as operating system.
In practice we have many operating systems like macintosh,linux,vista,xp. Out of all the most commoly used operating system is windows XP.