The Windows executable for the "Command Prompt" - at least for Windows 7 - 
is located in C:\Windows\System32

It is C:\Windows\System32\Cmd.exe   

If you use your Windows Explorer (file folder icon thingy) and go to the 
C:/Windows/System32 folder, and look in the folder, you'll eventually 
see an executable file, "Cmd" or "Cmd.exe". You can make a desktop 
shortcut link to it as follows.

1) Right click on the cmd file name; choose "shortcut" from the menu
 which appears. It will say "I can't make a shortcut here, do you want
 one on the desktop?" Click "yes" and a cmd icon will be placed on your desktop.

OR - OR - OR

2) You can right-click the cmd file name; select "copy" on the menu that appears.
 Then move your cursor to the desktop; right click and you'll get a menu,
 select "paste". AGAIN, you will get a cmd icon placed on your desktop.

End of choices. 

That icon on your desktop, when clicked, will open a "command prompt" 
window. Use it, like you use MS-DOS.