Here is a small tutorial on "How to attack on someone's PC with DOS" This technique is very interesting and simple.It uses "autoexec.bat" to run the program. Follow the following steps for the Successful execution of the Technique.

Step I ] The frist thing u required is create a .exe file using "copy con" command.
Note that the extension name must be .exe.
Step II] There will be a question in your mind , What the .exe file contains ? and What the
File Name is? . For this goto the step III.
Step III] When u creates the .exe file in dos , name it the ASCII character BLANK that is -:
Create the .exe file as follows.
"name" = Hold Down ALT+255 (a blank appears.)
c:\> Copy con "name".exe (here name is as shown above.) Step IV] Now the ALT+255.exe contains some ASCII characters which u have to findout
yourself.Here is just a hint .
There are some ASCII characters which reboots the COMPUTER again.
Or some hangs up the computer etc.
The .exe file looks like as follows.
c:\>copy con ALT+255.exe
f榦__»¶

^z
File saved.
Step VI] Now Open Autoexec.bat and add the word ALT+255 at the end of file which is your .exe file name
END ] When computer boots , it read autoexec.bat , in last line it reads
the .exe file name . This name is a blank space so that no
one can understand it simply viewing the file. AND computer boots again and again.

NOTE - : when u creates a .exe file , find out the ASCII word's combination yourself which produces various results such as BOOTING , HANGS UP computer etc.



or you can just do something much easier if you dont wana do this tut
Just open the autoexec.bat file (right-click > edit) and type "shutdown -s -t 00".....

What does "copy con" do?

writes to a file

or simply put, create a file....

but like stated by mathofaka, you type in the "content" of the file and in order to finish creating, you need a CTRL+Z (followed by press enter)

Interesting info there mathofaka......