Notepad is a native Windows text editor with limited features regarding coding business. If you have the knowledge you can code a software application by building source code but it's very complicated since there is no tool to help you compile, run and debug the application. I recommend using Microsoft Visual Studio 2010 because it's the best IDE used to build all kind of applications using a set of powerful tools and features. It has an integrated compiler, a very powerful debugger and quality libraries with the latest updates.
Upon starting the application a menu will be presented with options to choose based on your project. You can code from .NET applications to .ASP, .DLL and Java.
