If you use command prompt regularly and want a shortcut on your context to open it fastly then this trick is for you.If you go through simple process to open a command prompt then you have 2 ways
Type CMD in run command, Or
Start => Accessories => Command Prompt
In both process you have to go through a little long process, howz if you get Command Prompt in just your context menu and you need not to tweak with any system file and without installing any third party application.
By default in Windows 7 you will get command prompt option in your context menu but its hidden,to get it just press SHIFT key while right clicking on any folder and you will see Open Command Prompt Window Here Option in context menu.See belows screenshots:-
This trick also works in desktop context menu just do the same thing